Earlier quoted context omitted.
As a non-American who lives in US these days, I can assure you that there's nothing unique about the Americans' ability to hate each other. In terms of literally killing people over that, you guys are definitely far behind.
More Americans should visit the Balkans and learn the regional history. It's a beautiful area, and gives some perspective on the universal human capacity for irrational hatred. What I've never understood is how people can get so outraged over even minor political differences. If someone agrees with you 80% then that's an ally, not an enemy.
Pretty much any region has plenty of history that Americans should reflect on. E.g. whenever the American media and/or pundits talk about the "civil war", it's inevitably framed in comparison to the US Civil War. Except that was a very atypical "civil war", as those things go - fought by well-established governments using mostly conventional armies. And while it's still the most devastating war ever fought on US soil, its casualty numbers are minuscule by the world standards of what civil strife looks like.
To find out more about what an actual civil war looks like, one might explore history of civil wars in e.g. Russia, China, or even Finland.