Racism/Sexism/Bigotry can end up in logical fallacy territory pretty easily. "If women were unsuited for tech careers, there would be few of them in tech; there are few women in tech, therefore women are unsuited for tech careers" is a logical fallacy that I see around here pretty often. "Sexism" is just easier to remember than "Affirming the consequent".
But calling the problem there "sexism" has two major negative effects: it can lead you to believe that correct sexist arguments are flawed by their sexism, and it can lead you to accept affirming-the-consequent type arguments that aren't sexist. If something's wrong, you don't want to slam it for orthogonal traits, you want to slam it for the things that make it wrong.
