Was the issue not, because they allegedly made others feel uncomfortable? Would they have done the same to a group of pro-Palestinian activists if they had made others feel uncomfortable? Personally I doubt it.
They could legally not ask them to leave just because others didn’t like them, as covered by what I posted. Not much difference is there? What made them feel uncomfortable? As they do not appear to have been doing anything wrong, so it is who was sitting there, and you have to consider, the complainants just didn’t like him.