Imagine you are in high school, with 50-100 (idk the exact numbers) teenagers at a public place. A fight breaks out and some people start getting dramatic. OK fine...more people show up and things start to get over crowded, and certain parties are at odds because of the fight before. There is tension, so you call the local police to get everyone to leave before things escalate.
No one is leaving, you have a large group of people not going home and the cops come. Some people run, some people run their mouths and everyone else stands around the place they aren't supposed to be anymore. If you were in that situation, do you think running or talking shit to an officer would help your case? Hell no.
Is reaching for your gun the right thing to do either? No...but if you do nothing then what good are you as a police force? Mostly no incidents go perfectly smooth but police need to act. I'm not defending either side here because I think they are both wrong, but if no one is there to maintain order and no one is helping to diffuse the situation in either party, then things will go wrong.
No gun should have been reached for and everyone should have just gone home. Sorry you can't have a pool party because some people ruined it for everyone. We don't live in a perfect world and things go wrong. Things could have gone much worse than they did but bet your ass, where I am from and most people are white, if you remotely piss off a cop, you are getting in trouble.
We can't have police that is afraid to take action, and we can't turn everything into a race oriented problem like the media wants us to (if 9 out of 10 people in a group are black and you arrest 5 for breaking the law, that isn't "targeting black people" its targeting the people who broke the law (I get there are exceptions)). In the end of the day, that cop should be punished, and so should the kids that were making life/work more difficult for the police. For every mistake that happens, there is a moment where a police offer saves a life, but those stories mostly go unheard of because we like to focus on people making mistakes more than we do people making a difference. We need to make a lot of changes.