I know an American who was educated as boy in England but attended college in the U.S. After graduation, he spent a year in London with one of the big Wall Street investment houses. He would very much disagree that the anti-Americanism isn't a case of snobbery. A lot of upper class British people, are actually quite snobbish, especially if you are Catholic and have an Irish last name.
Very anti-semitic (anti-Jewish, specifically) as well. Also, in my experience, use the N-word quite casually. Make no mistake, snobbery in Britain is not what it used to be when absolutely anyone actually making his own living (rather than living off a trust fund) was automatically sneered at (and viciously, too) right along with ANY member of ANY minority group, but it's still there, alive and well.
In my experience, the British say things, very casually, about minorities that most Americans truly cringe at.
With genuine apologies to our fine British FReepers. Present company excepted.