Anyone who has spent a bit of time around especially elite college campuses knows that while, yes, sometimes students protest right wing speakers - sometimes this is perfectly right and good and sometimes you can argue that they go too far and the heckler's veto is rarely if ever appropriate but these things are always a bit more complicated than people make them out to be - it's pressure from the top that tends to discourage left wing speakers from coming to campus. There are academics and activists on the campus circuit who every knows are "controversial," quite often because of rather strong left wing views on things like war, carceral state, economics, racial issues, etc. Black "radicals," commies, Palestinian activists, etc. Watch those pots of money mysteriously disappear if you try to put your hands in them to fund a visit by one of these speakers. To put it simply, it's not controversial at all to advocate invading a country for lies, and then profiting handsomely off of that, but it is controversial to suggest that maybe, just maybe, when police are executing people in your communities that something more than accepting it quietly is necessary. Military and cops are good, the poor and the marginalized are suspect. And these are our liberal institutions!
Anyway, the administration and money have the power and more importantly the need to cater to power. The kids have protest. People get very upset about the kids. It's always revealing.
