The police, armed with increasingly lethal weapons, will endlessly escalate the arms race. Many SWAT teams are now equipped with up-armored tactical vehicles, essentially small tanks. These Rambo wanna be's saw too much embedded reporter film footage from Fallujah and want to do the same thing. The only difference is that these big gun, small d*ck LEOs didn't have the balls to try it as part of the 101st or 5 Mar Div.
Some of them.
Some of them are ex-military, and haven't learned that they're now CIVILIAN police and the mission is different.