We, the Royal We and not just the US, have seen that violence is the solution. Used to be if you didn't like something you either changed the law or went to court and then abided by the decision. Now? Ignore the courts, ignore the laws, and go after your own "justice".

I don't think there is any one overriding reason or ideology but rather, again the Royal We, are unwilling to spend the money on education, mental health, public health, and other things so they just fester and then explode.