I get what you're saying, Greg, but they're still such a thing as restraint, especially when you're not dealing with the asshole but a bystander to the scene who doesn't deserve it.
No question. The same problem happens when you have military in a place like Iraq, for example. Talk about a police state.
Furthermore, many of the examples quoted in that compilation have to do with far far less ambiguous circumstances, like doing a drug bust and breaking into the wrong house, shooing the owner dead. Or for a less dramatic example; harassing kids in the city for skateboarding. Or how about leaving valuables in the subway and pouncing on people who pick them up and don't immediately return them. Or pulling people over on the road and beating them up. These aren't cases where the cops where called in to defuse a situation, they just showed up on their own with an agenda. And if it happened to one of us here I'm pretty sure we'd be pretty outraged.
In case you haven't noticed I'm not posting stories like "cops beat up violent bank robber". Yes that would be wrong, but there are far worse things happening.
But the media are always going to seek out the horror stories of abuses. And to think that abuses are 100% preventable is a bit unrealistic, don't you think? I mean, we'd be holding police officers to far higher standards than the priesthood -- and they're off kiddie diddling six-year-olds for crying out loud.
Not to exonerate it in any way. Not to say some checks and balances shouldn't be put in place. I think internal affair organizations, while not entirely effective, a good step towards external regulation of what can be a fraternal affair. (Afterall, we're dealing with a president who thinks he doesn't have to abide to his country's own constitution.)
But my point is that I cannot think of any single job or profession where there isn't incompetence, abuse, misuse, bad behavior, illegal behavior, etc., in some derelict percentage of its employees. Granted, with the police someone can get hurt if not killed. But I also believe that there are damages at least as harmful, although not physical per se, because of the bad or incompetent people employed as teachers, judges, lawyers, government officers, meat inspectors, engineers, etc. -- people society is heavily dependent upon for health and well-being and even safety. The physical abuses are a lot more visible, sensationalist, and obvious. But things like white collar crime, cronyism, protectionism, and corruption just don't make good television and YouTube clips.
To think otherwise, IMO, is to be as guilty as the parent who sends their kid to college and then gets "shocked" that crimes are committed on campus -- as if criminal behavior universally disappears in humanity if you give the potential assailant a university library card.