Your hypothesis is that two "reasonable women" will enter IT as a result of Julie Ann Horvath and another former employee feeling ostracized at GitHub?
Besides, it seems possible that women who work at GitHub don't quit because JAH is gone, if some accounts are true (ie the Jane Doe on Medium article).
But you are right, the JAH incident itself probably doesn't motivate anyone to join IT (neither men nor woman).
Then again, perhaps eliminating drama from IT (by eliminating drama people) will in the long run entice those women to join.