I've traveled extensively ex-US the past year, Europe, Asia, north Africa, Central America, etc and echo what people have already said. There are a few rude people no where you go and no matter what nationality, however I've not had any issues being American. Most people are smart enough to understand that citizens and their government don't go hand in hand.
Let me ask you a question - What do you think of the current political situation in Switzerland? Not much, eh? Same for people in Europe.. they know the headlines but don't really concern themselves much with what's going on outside of their own country.
Lastly a tidbit from my recent trip to Mexico. I told my friends and family from the US I was going to the Yucatan and they said "That sound amazing!" "Have fun!" "Take pictures". And while in the Mexico I told me Mexico friends I was returning back to the US and the reply I got was "Be safe".
I wouldn't worry about ex-US travel. Be good to people you meet on your travels and they'll be good to you.