We need to leave this. Claiming she is both stupid and a woman is the sort of crass argument Momentum Bros make about this shit.
Supid woman is a sexist and dismissive phrase. Whether it is accurate is neither here nor there. It isn’t language a progressive should use because it carries history and meaning beyond its basic one. That’s the nature of language. It’s sophistry to argue otherwise, much like if a racist were trying to argue the P-word is just short for Pakistani, and I very much doubt you’d let them off with that.