i know its hard to look at it from a cops perspective but try to see it like this
there are about maybe 100-150 cops there and if a few people turn violent then the crowd can become a mob very fast and they are severely outnumbered so it is up to the officers to keep it under control.
maybe they did act a little too aggressive in this case but try and look at it from their shoes
sorry i had an uncle who was an officer and he was killed in a situation like this