I'm Swedish, so I'm from a country people have a lot of odd ideas about (like we're some socialist paradise of horny blondes)... but some of them are probably true, to some extent.
Also we think our stereotypical "that's racist!" depictions, like the Swedish chef, is pretty funny. Imagine if he was the Somalian chef, or Chinese chef - would they just laugh and consider him entirely unoffensive? People, and nations, should be able to laugh about themselves and how strange you seem to others.
Anyhow we (Sweden) used to be a conquering world power, back when Norway, Finland, parts of Denmark and Poland (who wasn't Poland back then) and such was just "The Kingdom of Sweden". That all ended centuries ago and since then we've not, as a nation, been at war. But that is how I see the USA.
You are a child of a nation, well teenager perhaps. Insecure and violent against all that could be dangerous to your unity. Basically you're us 300 years ago. Ready to fight anyone who looks at you funny, and prone to overly committing to anything. Be it the idea of freedom, your choice in religion, views on government regulation - basically everything. You'll find both extremes in the USA.
God hates the gays! - Gay marriage is legal.
No government oversight! - Regulate EVERYTHING!
God is the answer! - Actually like 30% of the people don't believe in God.
You'll pry this gun from my cold dead hands! - Ban all the guns! In fact: Ban all the weapons!
We are the 1%: Go trickle down economics! - We're the other 99% you're milking for money, go fuck yourself!
We want all the violence on TV! - No blood, or bruises, basically we hit people but no one is ever injured... well, maybe a small cut on the brow and some soot.
You're such a big nation and there's really just not one kind of American. There's no real national identity, there's multiple based on a lot of other things rather than "I was born in the USA". You're diverse, to extremes, and as a nation you're still trying to figure out what it means to have a national identity - because there's so many. I mean as a nation you're bigger than the entire EU. We're diverse as fuck so agreeing on anything is a right pain in the ass, and we're mostly just trying to agree on economics and regulations. At least you guys mostly all speak the same language
Anyhow I think this basic lack of a common identity and insecurity manifests itself in a kind of fear that makes you more prone to violence and you have a nation built on revolution, on fighting and being able to fight for what you believe in. You also don't know your fellow citizens in the same way as a more homogeneous nation does, you can't go to the other side of the nation or city and just find more people pretty much like you. You're strangers in a nation of strangers, and that sounds kind of scary too me.
So the short answer is: Yes, I think you seem prone to violence and you do glorify violence, or the capacity for violence, in a way I find worrying, as you brush over the consequences. But then some of you are probably just like me, it's bound to happen in such a diverse nation.
The point is that you're still a young nation. Hopefully you'll become more unified a couple of centuries from now and stop acting so insecure, juvenile and scared. Until then the rest of us will try to enjoy the show and hope you don't break too much growing up, because if such a large gathering of diverse people like you manage to unite in peace then that means the rest of us can too.