It's almost like America is essentially 50 countries taped together and if you treated someplace like Europe as one giant country you'd see just as many violent incidents happening.
Not really.
America has a population of over 300 million, so yes, the amount of murders is going to be much greater than a country with a smaller population. But when we look at per capita deaths, the United States is clearly an outlier among OECDs, which, incidentally, is a group that Western Europe falls into, and depending on where you draw the line, Eastern Europe as well.
I actually looked up the murder rate globally, and the United States does have a higher murder rate (5.35 per 100,000) than most European countries, even ones in the eastern part. Yes, Russia is much higher (10.82) but then you get stuff like, say, Portugal and Spain (0.64/0.63). So, no, if the European Union became a single country day, it might have more total deaths than the US, but per capita deaths would still be lower.
But even then, while I'm not trying to sound morally superior, the US gun culture strikes me as absolutely bizzare. Within my own lifetime, I've beheld the Port Arthur Massacre (though a bit too young to remember it) and the Christchurch Mosque shooting, and both Howard and Ardern, leaders on opposite sides of the aile, acted immediately. The US seems to have a mass shooting every other week.