I posted this somewhere else, but you brought it up and I thought it applied here as well. You ask why our police forces are becoming more militarized. Look at their applicants. I've been in the Marine Corps for going on 16 years. In only 2 of those have we not been at war. During those 16 years, I've seen many a Marine come and go. A lot of them, upon honorable discharge, apply to their local LE entity whether it be city/county/state/federal. Now, those are the guys on the street. Those are the guys that are planning operations. I'm not saying we have a bunch of testosterone laden, PTSD ridden vets running rampant on our streets. What I'm saying is you have a bunch of guys who's idea of policing is kicking the door in and taking down bad guys. Right or wrong, that's how they were trained and most LE units do nothing to change that idea. Add that to the fact that our federal gov't gives away MRAPs, body armor, optics, NVG's, etc like they're candy to whatever podunk police dept wants them and you have a militant police force. These aren't the end all be all answers to your questions, but I believe they are big factors.
On a lighter note, I for real thought that black chick on the left side of the screen shot for your video was wearing a flower for a hat lol. I had to double take.
Further edit: I didn't watch the video prior to posting my original statement. That guy is awesome. Great speech and so true. I said this before. If the black community would concentrate on fixing black on black crime, childbirth out of wedlock, low graduation rates, high unemployment rates, etc, etc within their ranks, the rest of the country might listen to them. But when they off themselves in record numbers and then turn on a single cop when he protects himself, no one wants to hear it. Is Michael Brown's life now more important because a white cop shot him vice the thousands of black people that were shot by other black people? I don't think so. Apparently they do.