There are lots of reasons why people resist arrest and they run the whole spectrum: drug-addled, testosterone-fueled, hard-headedness, aversion to authority, lack of impulse control, just plain being the assholes they are all the time. But there are also people who have no idea why they are being arrested and some of them are being arrested for no good reason to start with and many of them struggle with officers to varying degrees. There also are those who actually try to comply but they have one or two officers on them and they're lying facedown on gravel on top of asphalt and the officer keeps yelling 'put your hands behind your back' and they keep saying 'I can't' or 'I can't breathe' because there are 400+ pounds of police literally on their backs. And then there are those folks who don't actually resist at all but the cops have already roughed them up and need to explain that somehow.

I have a fair amount of experience in the criminal justice system. I was a criminal trial attorney for ten years or so trying all levels of cases from drunks to murderers. I - and every criminal defense attorney I've ever known - had many clients who'd been beaten by the cops. Some deserved it, sure, but some didn't. My experience was that the worse the beating, the more serious the charges by the police. In other words, if my client had a few bruises, he'd be charged with obstructing an officer. If he had a broken arm, he'd either be charged with a felonious assault on an officer - or in one case I took to trial, an officer would plant drugs on him as well as charging him with a 2nd degree assault on an officer. Hard to believe, isn't it? I truly wish it weren't true, but cops own the streets and if you make the mistake of questioning that somehow, or if they think you're a criminal whether they have evidence of that or not, you're in deep shit.

You ask a reasonable question: why do people resist when it's going to end badly for them? In the exteme heat of extreme moments, reason can desert people, and that includes suspects, police, bystanders, even witnesses who just happen to be there. But a charge of resisting arrest or obstructing an officer is often just a catch-all police use when they want to arrest someone and they have nothing else. Often the underlying charge is bullshit and they know it, but they can always make the resisting stick because juries simply won't believe officers will lie under oath. But every prosecutor, judge and defense attorney knows some cops lie sometimes, and some almost every time they take the stand.

A big point for last: societies have had police of one sort or another for thousands of years. And for thousands of years people have resisted being taken into custody by those police. People physically resisting is a routine part of the job description of every police officer. So for thousands of years, police have developed techniques and training to deal with people who resist. The officer in this case most certainly received extensive training on subduing and controlling suspects using the minimum force required. This officer ignored that training most likely because that's the way he always acts on the streets - just like SDH said, he did it because he can and he wants everybody to know he can - and I'd add he probably also likes hurting people. Some % of police enjoy that aspect of the job. I realize that there are plenty of times it takes more than one officer to subdue and control a suspect. I also realize a lot of people resisting arrest bring their subsequent injuries at the hands of officers (or at the batons, boots, flashlights, tasers or guns of officers) upon themselves. But in this case, this suspect was clearly no longer able to resist and yet the officer killed him anyway; the officer ignored his training and turned an arrest into a murder.