There will always be a need for LE as long as alcohol is being brewed and distilled.
I too had some bad experiences as a law-abiding young man with a mouth on him. A friend of mine had his arm broken for no reason. Repeat: for no reason except so that a LEO could assert his dominance over somebody who had violated no law - and wasn't even suspected of any violation.
I got over it. And I've gained a little perspective, too. Compare your worst cop story to what happens every single day in Argentina or Mexico. Sure, the militarization of our civilian police forces is unnecessary, counterproductive - and scary. But those same cops are our lifeline and our last stronghold against creeping fascism.
They're not much of a lifeline when they seem to have no problem doing their bosses' bidding. So our guys aren't as bad as their guys... yet.