But in recent weeks, the same discomfort that many Americans Jews feel about the current Israeli government, and in particular its continued occupation of the West Bank, have been reflected in some of the tours. An American anti-occupation group, called IfNotNow, has organized walkouts by a few Birthright participants, hoping the resultant publicity will inspire other young tourists to make the same gesture, and pressure American Jews to reassess its support for Israeli policies.
In June, that led to a chaotic scene on one of the tour buses. Bethany Zaiman of Washington stood up and announced that she and four others would leave the bus to "learn about the occupation from the perspective of Palestinians," and would visit the West Bank.
The Israeli tour guide interrupted her several times, and — as seen on a video that was shown on Facebook on June 28 — erupted as the group was leaving.
"No Palestinian is going to send me away from here!" the guide said.
Moments later, a male Birthright participant wearing a white T-shirt and holding what appears to be an American flag, pointed at Zaiman and said: "Guess what's going to happen. You're going to get killed, you're going to get raped."
“There is a tremendous fear about speaking honestly and openly about these Israeli, about Palestinians struggles, about these complexities, because you could lose your job.”
IfNotNow helped stage another walk-off on video a few weeks later. The second group left a Birthright tour and visited a Palestinian family in danger of being evicted from their home in eastern Jerusalem, which was occupied along with the rest of the West Bank in 1967 after the Six-Day War with Israel's Arab neighbors.
Though only a few participants have engaged in walk-offs, the protests have been widely shared on social media and have helped shine a light on the growing disillusionment with Israel that many young American Jews feel.
Dubbed radical, anti-Israel and anti-Semitic by some critics, members of IfNotNow say they are tapping into anger at established U.S. Jewish institutions such as Birthright, which they say have hidden the reality of Israel's occupation of Palestinian territories, and acted as apologists for a government that has increasingly moved to the hard right. (The group takes its name from a well-known saying of the ancient Rabbi Hillel: "If not now, when?")
Birthright is "so afraid of the occupation that they're trying to hide it" from young American Jews, said IfNotNow member Clare Jordan, who was one of a group of activists who came up with the #NotJustAFreeTrip campaign.
Meanwhile, Zaiman, who had started getting involved with IfNotNow just before taking the trip to Israel, told NBC News that all her "requests to meet Palestinians were ignored" by Birthright.
A spokesman for Birthright Israel denied the organization had a political agenda.
LIFE ON THE EDGE
"All participants attend a geopolitics module where the complex issues of the Middle East are addressed without endorsing any specific agendas, opinions or beliefs," he said.
Birthright, which ran 24,650 trips for young Jewish adults from North America this summer, is funded in part by the Israeli government and also by wealthy American donors, including its founders, billionaire philanthropists Charles Bronfman and Michael Steinhardt. Earlier this year, Republican mega-donor Sheldon Adelson, a billionaire casino owner, gave Birthright $70 million.
The organization "provides the gift of a free education experience to Israel for Jews worldwide between the ages of 18 and 32 so they can explore their Jewish identities, strengthen their connections to Israel and experience its diverse society," said the spokesman, who asked not to be identified.
The spokesman said those who walked off were a tiny fraction of the program's participants, and had a political agenda.
"They chose to leave the trip early as a means to generate publicity for their causes," the spokesman said, adding that participants are free to extend their trip and travel anywhere in the region before returning home.
Jordan said it was her Jewish identity and values she was raised with that led her to IfNotNow. She and her sister Leah Jordan — a rabbi who is also active in progressive circles — were raised to love Israel, she said. The family attended synagogue regularly and the sisters went to Jewish summer camp.
"I grew up feeling deeply Jewish," said Jordan, 29-year-old Kansas City native who recently moved to Jerusalem to study Arabic.
But in her teens, Jordan realized that not all was how it had been explained to her at camp and in the synagogue, she said.
For her, a change of perspective came during a trip to Hebron, a Palestinian city with a population of over 150,000 in the West Bank. Hundreds of Jewish settlers, who trace the Jewish presence in the city back to the Old Testament, are guarded by Israeli soldiers who, according to rights activists, regularly and unnecessarily raid Palestinian homes. Over the decades, Palestinian streets have been cleared, shops shuttered and homes emptied, with some areas cleared of any Arab presence.
"All it took was a split second and I realized this was not a conflict — it was a brutal occupation," Jordan said of her visit to the city.
IfNotNow, which was founded in 2014 during the last Israeli war in the Gaza, now works in 16 cities in the U.S. and says that up to 10,000 people have attended its 350 protests in the last two-and-a-half years. Among their targets have been powerful pro-Israel lobby group AIPAC, and the network of Jewish camps, Camp Ramah. They also protested when President Donald Trump's former adviser Steve Bannon spoke at the Zionist Organization of America, and organized a demonstration in Washington after the U.S. announced it was moving its embassy to Jerusalem, which infuriated Palestinians.
According to Rabbi Sharon Brous of Los Angeles, a who leads a progressive non-denominational congregation in Los Angeles, IfNotNow is part of a generational shift among Jewish Americans who are alienated by signs of growing illiberalism in Israel.
"There is an enormous number of young American Jews who felt that the only option they had was to buy into the party-line script of the right-wing nationalist support of Israel, or to abandon the Israel conversation altogether," she said.
Members of the group are more likely to be critical of the Israeli government than their parents and grandparents. A major 2013 Pew survey of American Jews showed that only a quarter of those aged 18 to 29 thought the Israeli government was "making a sincere effort to bring about a peace settlement with the Palestinians."
U.S. resistance to Israeli policies has existed for years, but it picked up speed after Trump was elected, according to Brous and others NBC News spoke to. The close relationship between Trump and Israeli Prime Minister Netanyahu — a hawkish politician who is in a coalition with Orthodox and ultra-Orthodox parties — has galvanized many, given that a majority of U.S. young people as well as Jews do not support the president. Netanyahu's links to the U.S. evangelical Christian community has also worried many liberal Jews.
"Some people are asking — how did all this happen?" said Brous.
EFFECTS OF WAR
"How could it be that my sweet Jewish democratic Israel is now detaining journalists at the border and not letting people into the country and interrogating people based on their political views?" she asked, referring to the recent detention and questioning of Jewish journalists and activists as they arrived or left the country.
Among these was Peter Beinart, a prominent liberal American journalist who says he was held and interrogatedabout his contacts and activities at Ben Gurion Airport in early August. Netanyahu later said the detention was a mistake.
The change in attitudes among American Jews has traditionally not burst into the open because criticizing the state of Israel has long been anathema to community leaders, said Brous.
"There is a tremendous fear about speaking honestly and openly about these Israeli, about Palestinians struggles, about these complexities, because you could lose your job," she said. "In the name of loving Israel, we have created a firewall to protect Israeli politicians and Israeli policies that I believe are ultimately undermining Israel's Jewish and democratic nature."
Another example of what many on the left consider to be an illiberal trend is the list of 20 organizations Israel has banned from entering the country because, the government says, they back the BDS movement, which supports boycotts, divestment, and sanctions on Israel. While it has been fiercely resisted by Israeli officials, it continues to make headway. Last week the pop singer Lana Del Rey became one of many performers to cancel appearances in the country, in her case at a major music festival.
Even prominent mainstream Jewish leaders in the U.S. are starting to publicly criticize Israel's government.
On Aug. 13, Ronald Lauder — president of the World Jewish Congress — wrote an op-ed article in The New York Timeslisting a litany of complaints and government U-turns, including the controversial nation-state law which many believe demotes non-Jewish minorities to second-class citizens.
"These events are creating the impression that the democratic and egalitarian dimensions of the Jewish democratic state are being tested," he wrote.
Another Jewish figure who was recently detained and questioned was Simone Zimmerman, a co-founder of IfNotNow who was stopped on the Egypt-Israel border in early August.
"They asked me if I knew Palestinians repeatedly," she said. "In their eyes, knowing Palestinians, caring about Palestinians, having anything to do with Palestinians is a threat."
The incident, which lasted several hours and was a "warning," should be put into context, she said because non-Jewish travelers regularly endure far worse treatment.
Zimmerman was briefly in charge of Jewish outreach for Bernie Sanders until an old Facebook post where she referred to Netanyahu using expletives surfaced and she was fired.
While Zimmerman and others are proud of what IfNotNow has accomplished in opening up the discussion and embarrassing major organizations such as Birthright, she acknowledges there is much still to do and "most of my community is still in denial."
Yael Patir, the Israel director of Washington-based liberal Jewish think tank J Street, which supports a two-state solution, says that 10 years ago it wasn't clear how little space young Jewish Americans had to become involved.
"I don't think it was understood the extent to which young American students didn't have a place," she said. "There is a sense that you cheated us or lied to us or hid the truth."