The exact problem here is that cops are not trained, or just don't, act calmly and with reasonable force in these high stress situation. I mean that should be expected of untrained civilian protesters, but cops kind of have to make good calls, in difficult situations. Thats the job. If you can't hack it you shouldn't have the badge. Bad cop doesn't just mean bad person.
It seems like we are seeing way too many of them just can't handle these high pressure/high risk situations. They may be very nice people, but just not cut out for this work.