I think something folks are missing is that a lot of, if not most of, people in the activist sphere are perfectly aware of the antisemitic undertones, messages, and individuals within their movements.
They just don't really care.
Antisemitism is seen by most left-ish goyim as a lesser prejudice, something that's not really an important issue. So when someone they're organizing with harasses, assaults or vandalizes random Jews, Jewish-owned businesses, JCCs, or shuln, they're perfectly happy to brush it off. It's a minor blemish on what they feel is a noble and righteous movement, not a big deal overall. You can point out the ways in which they are harming Jewish people and communities by spreading antisemitic talking points and obvious lies all you want, but they're still just going to reply with a non sequitur about Palestine.
The students at Columbia are perfectly aware of the naked hatred of Jews on display in the off-campus solidarity demonstration outside the gates. They are aware they are creating an environment in which the majority of Jewish students do not feel safe or comfortable being on campus.