Spraying chemicals directly in the faces of nonviolent students and then beating the shit out of them with batons.

Violently suppressing peaceful protestors is my guess.

To make it look like the protestors are violent. They wouldn't call in those troops if it weren't for those savage antisemitic protestors, right?!?

Great question.

It's hard to crack down on dissent without them.

Because the American Power Elites believe Might Makes Right and the riot police are their most willful and most violent goons.

Depending on your biases, either to try and maintain order to prevent it from becoming a riot, or to intimidate and assault protestors.

Given the history of police and protesting college kids, it's probably supposed to be mostly an intimidation thing.

To beat pregnant

They don't, they just want to scare the kids into but expressing ideas they don't like. Which is very illegal but they don't care