the punishment for being an idiot these days is to get assaulted? if we are all so intelligent here, how can we not understand that not everyone on the planet is? It also doesn't have to be one or the other - the guy in the wheelchair can be a dick, and the reaction of the cop be so OTT that he deserves to be fired.
What if one of us intelligent people has a bad day while near a cop like this - should the correct and proper punishment for being shitty if 'insert_mitigating_circumstance_here' be getting assaulted by a cop?
The whole point of being one is that you undergo a supposedly strict selection process, and specialised training in all sorts of things, including how to deal with jerks. The very nature of the job dictates that you are going to be dealing with idiots all day long, including a great many people with a low IQ and/or behavioural problems (the very fact that he was being thrown off for what he claimed is a pretty clear indication he isn't quite all there).
The guy in the wheelchair might be the biggest douche on the planet, but that has zero to do with the fact this cop was an out and out cunt
As for 'justice' - you think a guy who worked at walmart who assaulted an asshole cutomer in this way would be demoted, or sacked on the spot?