When men see in a war zone that problems can easily be solved by killing others and threatening the rest with guns, they remember this.
When I was a child, my parents told me how awful the Nazis were because they busted into houses inthe middle of the night and arrested people for no good reason.
That is precisely what our taxes paid our army to do in Iraq and Afghanistan. They did not speak the language, they could not understand the people, they were simply well equipped and well armed thugs. People spent months in Abu Graib and no one knew why they had been arrested.
Of course, after the war, the same troops needed work and since they had great weapons training, they joined the police.
The chickens have come home to roost. Some of the ex military, like Tim Mc Veith, John Allen Muhammad (the DC Beltway shooter) and the latest Dallas shooter did not become cops, They simply became mass murderers.