With absolutely no facts specific to the latest news, I don't want to cast aspersions on American men and women in uniform, just put it out there:

1) I have heard from some of the young enlisted folks who've been there, then rotated out, and most of them hate it. They feel that many locals are thoroughly two-faced if not worse, and they feel like they've tried to be friendly, helpful, and constructive to the locals yet the whole time they're sitting ducks.

2) These same young enlisted folks have not been trained in police procedures. They are warriors put into a policing role. (This seems to be one of the factors the English forces have taken more into account, yet they, too, have had some bad incidents with the locals).