When you get right down to it, I think the biggest issue with American people is that we don't respect life.
I was browsing Twitter a little while ago and I was reminded of this "heartwarming" story of an old man who shot and killed a fleeing woman. First of all, even if there was nothing fucked up about that it's hardly worth bragging about. Secondly, a human doesn't cease to be a human just because they've commited a crime.
We're raised from a young age to think gun fights are cool via action movies and guys murdering over property is portrayed as completely normal. This is why mass shootings are so common here and nowhere else: We've made it far too easy to not see other people as people, it transcends even the old "Us vs Them" mentality with regards to race and creed. Whites kill each other way just as easily.
Oh and don't bother reading that thread, it's a sickening mix of chauvinism and mysoginy.