My theory is they don't go into STEM because of asshats like you. When they do, they go into fields where asshats like you aren't welcome. For example, my workplace has a firm "no asshats" policy, and, guess what, lots of STEM women.
Exactly, I work in a similar environment and I'd say that on average the women actually out-perform the men.
From my 70 year old mother who still designs railways for a living: "Of course we're better, we had to be just to get through school and stay in the game."