In 2016, Birthright added a mandatory two-hour lecture on geopolitics. Birthright also spent a year developing nearly two dozen new optional activities involving Israeli Arabs, including a visit to Givat Haviva, a center that fosters cooperation between Israel's Jewish and Arab populations.

Those activities are currently available to Birthright tours, although only some tour operators use them. They have prompted complaints on the right from Jews who felt that Arab voices were unnecessary on a trip intended to bolster Jewish identity, as well as complaints on the left when Birthright paused them temporarily for fine-tuning.

Activists say the new programming doesn't go far enough. In the fall, J Street U, a liberal Jewish organization with 60 affiliates on college campuses, circulated petitions asking Birthright to include at least one Palestinian speaker on the occupation. J Street U has also rolled out its own alternative free trip to Israel this summer, which will take students into the West Bank to meet Palestinians and Israeli settlers. Organizers say it is meant to serve as a model for how Birthright could change.

IfNotNow has called for a boycott of Birthright.

Mr. Lurie said he has spoken to both IfNotNow and J Street U about their protests.

"If your goal is to make Birthright better, I'm on your side," he said he told them. "But if your goal is to destroy Birthright, I'm totally against you."

Charles Bronfman, a co-founder of Birthright, said he understood the desire of young Jews to learn how Palestinians viewed the conflict. "I'm not going to say they don't have a point," he said. "But that is not Birthright's job."

"If they have something to teach us, let's talk about it," he said of J Street U's efforts. "Maybe we have something to teach them."