That might be it's own problem, but I do not think it is THE problem. I would guess that very few Seattle police officers are ex-military.
I also don't want to tar everyone with the same brush. Although the institution is corrupt, it is not fair to blame all police officers for the acts of some police officers. Most of them are just trying to make a living.
Sometimes the incidents that happen are in a sense "honest mistakes". Admittedly, the case that started this thread wasn't; he "lost" it without real provocation. Most of us have had a teenager mouth off at us, without us grabbing her by the hair and throttling her, and flinging a shoe is not that big a deal. He's got "anger issues" that he can't deal with.
But sometimes police officers do make honest mistakes--maybe even killing someone but not intentionally. That case where the police officer at the BART station summarily shot a suspect probably really was a case of the dummy spacing out and thinking he is pulling out a Taser not a gun (but why oh why do they think they need to show force AFTER the suspect is subdued and compliant?! Who is training them this way, and why?!). I don't think that they are motivated to randomly kill people without provocation--more likely, confusion, poor training, and a certain paranoia insofar as they DO get shot or shot at from time to time "in the line of duty". Most of them are just trying to make a living, and caught up in a web of corruption they didn't create.
Similarly it wouldn't be fair to blame soldiers for the war. It's also counterproductive because they don't make policy. The people who do make policy are insulated from criticism and live in decadent luxury in toney neighborhoods on the banks of the Chesapeake and other favored haunts, while the soldiers are subject to a variety of deprivations and injustices--for example, many of them get "Dear John" letters and end up with alimony, child support payments, sometimes for offspring that are not theirs after having been cuckolded while they were away, sometimes getting cleaned out of all personal property (this happened to my brother; he came home and she was gone and so was everything they owned. He got the bills). My stepfather got handed a bill for the welfare benefits that his wife and her boyfriend racked up while he was in Vietnam, while she was also collecting his salary on top of welfare.
Many of them end up with disabling injuries, and their supposed benefits don't cover the catastrophic costs of dealing with the situation.
There is a problem, that has been mentioned briefly, that soldiers come back with a greater propensity for crime and unprovoked violence than the population at large. Bear in mind that it's still only a relatively few bad apples, and sometimes soldiers themselves are victims of soldier crime.
