This is very true. Part of it is due to citizens of other countries only have the ability to base their opinions of the US by who they meet. Unfortunately they usually meet the insufficiently_thoughtful_persons. I've seen many tourists get in trouble, while us Sailors usually never got into trouble. We always had a briefing on what and what not to do before we pulled into a foreign port. Regular (non Navy) tourist put on the "Ugly" American act, believing that the people of those countries should speak English and that the US laws were the only laws that applied to them. While we had the fear of the Captain put into us. Not saying Sailors never got into trouble, just less than the average tourists, for the most part from what I have seen.
No matter what country you visit, you should always research it, whether it is Canada, Greece, Korea, or wherever. It will save you a lot of trouble and you will probably enjoy the visit even more.