When you dress like a soldier, carry the same equipment as a soldier, talk like a soldier, train like a soldier (and in many cases, alongside a soldier), and you're told that you're fighting a war, then sooner or later you'll feel like a soldier, and then you'll start acting like one.

The problem with that is that the mission of the soldier and that of the cop are fundamentally incompatible. The soldier is there to kill the enemy and break his stuff. The cop is there to impartially enforce the law with the least amount of force necessary for the job.

Lastly, there's a psychological aspect to cops that look like stormtroopers. When even the non-criminal element of society raises an eyebrow at the sight of a cop who looks like the soldier of an occupying army, then you have a perception problem. Our boys and girls in Iraq and Afghanistan have learned that you can get the population riled up against you if your bearing and appearance are overly aggressive. They're taught to not kick in doors that don't need kicking, to remove the dust goggles or sunshades before talking to locals (making the eyes invisible depersonalizes an individual), and generally try to avoid losing the goodwill of the populace through moderation of force. Now, if our soldiers have learned the value of even these small measures to avoid alienating a foreign populace, why are so many cops still in denial about the cumulative psychological effect of hundreds of incidents where a SWAT team busted into the wrong place, dragged the wrong folks out of bed with the aid of automatic rifles, flashlights and balaclavas, or shot the wrong people dead?

[M]ore people need to speak out against such police tactics, or they will continue with the implied consent of the citizenry.

why are so many cops still in denial about the cumulative psychological effect of hundreds of incidents where a SWAT team busted into the wrong place, dragged the wrong folks out of bed with the aid of automatic rifles, flashlights and balaclavas, or shot the wrong people dead?