"No one ever went broke underestimating the taste of the American public"   ~   H.L. Mencken

The word "taste" does not mean the same thing as "stupidity".

There were many very intelligent people who liked Michael Jackson's product. They did so from an emotional basis, most likely. Also possibly from the "herd mentality".

The average American may not have quite the IQ measured in Japan or Israel, but we hold out own with the rest of the people of the world. We are a dammed sight more creative too.