The reason they are protecting her, is because of the us vs them mentality. Cops do risk their safety and so its reasonable for them to be somewhat guarded. The problem is that what most in dangers cops is not having control of situations. The solution they found was from the military. The military picked up its methods in war, and that is very different situation than what police face. Further, we have a gun culture so any violence has the probability of becoming lethal in ways that other societies do not have. So, when a cop goes into a situation, the first thing they try to do is establish order through their authority.
The problem is that because this is not war, and they are servants of the people they are trying to serve, their military tactics cause other problems that the military does not often if ever have to deal with. Civilians are not combatants. Combatants are people that are looking to kill you any moment they see an opening, so soldiers on the battlefield need to use force to establish ultimate control. Police are not on a battlefield, but, they are also not as safe as the main populace.
Because we do not have a hybrid approach we train police to be like soldiers and instill the same mentality as if they were. This is a huge reason they have the us vs them mentality.
The reaction of society is to see how police act, and respond. Some will try to appease police, while others will not want to give up their freedoms. The problem with the first method is that people are not trained so even when they do try and follow what is asked they may run afoul and get killed as exampled by the guy that tried to grab his shorts. The problem with the 2nd is that cops seeing the people not responding to their demands see that is a threat and they increase their force to establish compliance. Both cause the vast majority of the risk to be on the civilian and they bear the brunt of of when things go badly, whereas the police with their training often displace any risk.
To hold people accountable is 100% needed, but, it cannot be in a vacuum. Police need to be trained differently. Its not civilian's fault for how police are trained, and its not their fault that police have built an us vs them mentality, but, we must understand that we have trained police to in large part be this way. This should not be a pass, but, it does need to be addressed in the long run as punishment will not fix this.