I think questioning people who claim to be from another country - say Wales to pull one out of the air - and obsess over what they see is wrong with the United States is not an insult per se. It is a point to make in a debate about U.S. politics, etc.
Plus, I think that it is likely that they are socks of another poster and they use the claim of being from somewhere else as cover.
I would feel like an idiot if I went onto the Canada Message Board, and started droning on about the whigs vs. the torries or whoever they have.