How is that stereotyping? He didn't come out saying "all Americans are dumb, iliterate, and about 100 lbs overweight". _That_ would have been stereotyping. By contrast, his post was a fairly mild and inoffensive "in my experience, the Europeans I know are more cultured". Are you reading more into it than is there?
voting down because this sounds like a bad faith reply: it assumes the poster is wrong and demands proof, rather than admitting a lack of understanding and asking for guidance.