Well, I'd say in regard to US in the world wars and them everything else are completely different. I'm thankful they joined in the World Wars, but it pisses me off that they always try to make it about them. In a movie about the team that stole the enigma machine, they rewrote the guys from British to American. I think their media trays to portray them as the driving force behind the campaign's while shitting on everyone else who fought for it.
In regard to Vietnam and the Middle East, America invaded to fight what should've been a civil war and then to create anarchy, and they were fucking idiotic to do so. Here in Ireland (Or in my family and friends), they're kind of seen as punch-happy assholes who see a problem and try to use military wrath to vaporize it.
Hitler is, and I HATE to make this comparison, like Trump (Or Bernie, I guess) in that he had minority support, but his supporters were super passionate and dedicated. Anyway, I think he's given an unfair spotlight. The other European countries were also super anti-Semitic and tried to keep Jewish refugees out and in Germany. Sure, Hitler was worse, but not by THAT much, and no one ever brings up other countries' anti semtisim. Hell, the allies didn't even fully liberate the death camps, they kept all gays as prisoners and just transferred them, which gets no attention. Hitler's genocide conquering isn't even that much worse than Andrew Jackson's trail of tears. Still, he was a douchebag, just so were a lot of people who won the war.