"In the American Jewish community, it is extremely difficult to engage and be active in a loving and critical way," Brous said. "So I understand why young people now are looking for ways to make their voices heard."
In an email, Birthright said the protesters "chose to leave their trips early as a means to generate publicity for their cause," adding that the group welcomes diverse views and questions as long as they are constructive and shared respectfully.
"Birthright Israel is an apolitical educational program that does not condone use of its platform to disseminate one-sided political or social agendas," a spokesperson said.
Rabbi David Wolpe is among those in the local religious community who found the protest inappropriate.
"I understand people want different kinds of experiences when they go to Israel," said Wolpe, rabbi at Sinai Temple in Westwood. "But I think when you sign up with a trip, you have an implicit and maybe explicit commitment to the experience of that trip. ... I didn't see it as a right or left issue, I saw it as a good-faith issue."
Taglit-Birthright Israel was launched in 1999 by a group of Jewish philanthropists in collaboration with the Israeli government in response to concerns that the diaspora was not as engaged in Jewish life as previous generations, said Leonard Saxe, director of the Cohen Center for Modern Jewish Studies at Brandeis University.
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Since then, the program has sent about 650,000 young adults from more than 50 countries on the 10-day tour.
Some of those who quit the program said that they don't reject the concept of a trip such as Birthright, but believe it needs to be more inclusive and provide a range of perspectives.
Among the complaints was that the program had stopped dedicating part of the tour to meeting Israeli Arabs.
Birthright said it had only temporarily postponed programs that explore the "joint society between Jewish and Arab citizens of Israel" in the fall of 2017 to refine them and ensure they were as "productive and impactful as possible."