I don't know if it's still the case now, as I haven't been there for at least 15 years, but I used to find most Americans were very insular/parochial in their attitude, with very few having travelled outside the USA. Hence plenty of scope for some pretty wacky ideas about foreign governments/foreigners. The exceptions were the people I used to meet on business trips who were working for the same multinational pharma company as me - they had a much more informed global outlook.
Most "ordinary" Americans who we met on our holiday travels were very polite and helpful, a strange paradox really. We had three very long road trip-type holidays over there so we were frequently well away from the usual touristy places. Most people had no idea where Wales was, if indeed they had heard of it at all!