Police in other Western countries receive significantly longer training courses than US police do. This is an issue rarely discussed in this topic. If people want de-escalation, they need to fund the longer training regime and more importantly pay for it.

Short hair is pragmatic, but more importantly, it is a personal preference. Nobody should be criticized for wearing short hair. Doing that makes you no better than people who talk about "long-haired hippies" disparagingly.

EDIT:

Wow hivemind. It's for a similar reason that, in less hostile environments (say, machine shops), people with long hair put their hair back. It's like nobody's ever seen Bomb Girls before (much less any of the much more graphic images of, say, lathe accidents).

I'm not suggesting that the warrior mindset is acceptable...merely that, if they are going to carry themselves that way (i.e., as jackbooted thugs), they should probably go all the way.