Gromit
International Man of Misery
You can't stop a stampede that's started.Which is utterly stupid. If a crowd starts crushing or stampeding, then there's not going to be anything that a handful of cops on the scene are going to be able to do to stop it. In fact if anything, given how poorly trained US cops are, chances are they might panic, start shooting (because as well as being poorly trained, they're often itching to murder someone, preferably someone black) and make the situation even worse.
I would challenge any such idiot to explain exactly how a few cops are going to stop an already-moving crowd of hundreds to thousands of people.
You stop it from happening in the first place.
Which is, I believe, how people are suggesting better resourced policing might have helped.