I agree with some of what you say John but I just have to defend Americans a bit. I lived a few years in Chicago and my experience of the many friends I made while I was there is that they aren't as insular as individuals and they appear en masse. My friends, admittedly well educated people on the whole, were interested in and knowledgeable about the rest of the world. Often more so than I. Also I believe the numbers of passport owners in US is nearer 40% than 18% and rising fairly rapidly.
As for the gun issue I'm with you on that. I do think the NRA is wrong about a lot of things. However, yet again I think the numbers are skewed. I've looked it up after reading this post and apparently only about 35% of Americans households has guns (legitimately) and that percentage is falling. It was over 50% in the late 70s. It also appears that, even amongst gun owners, the number of people who feel that they have any kind of affinity with the NRA is quite small. Most feel that the NRA is an extremist organisation and not representative of the vast majority of Americans.
Now, it may be that I see Americans through rose-tinted spectacles because my experience of them is that they are kind, funny, thinking people but I also believe that most anti-American feeling is based on a skewed picture of the people as a whole and not allowing them to be individuals. It's very easy to believe generalisations. After all, the Germans have no sense of humour, the French all smell of garlic, Spaniards are lazy, Italians are sleazy, Swedes are sex-obsessed, the Irish are drunks and all Dutchmen wear clogs. Not my experience of any of these I must say...