Your sentiment is 90% of people supposedly being or seeming like being stupid. I assume that you use stupid in a colloquial sense as I don’t believe you think 90% of people are disabled. The colloquial sense contains quite a lot of contempt though, enough to qualify as misanthropy.

If you don’t like misanthropy, avoiding overgeneralisation like 90% of people being something, even in informal situations, helps a lot.