GitHub has, since the Horvath incident, made it pretty clear what kind of person they want to hire. And, frankly, that's fine.
There are plenty of places where I, as a competent white male, can get hired and promoted without difficulty. The fact that Github isn't one of those is not a systematic problem. More power to them.
No it is not. Either we are all allowed to discriminate or none at all. If only some must have power to discriminate - I prefer the status quo. Since I like the white male privilege. I am fine with society without privilege. I will fight tooth and nail against one in which my privilege is transferred to someone else.
If GitHub is rejecting otherwise qualified white males for employment they are opening themselves up to legal liability. I cannot imagine some of their statements wouldn't serve to hurt them in a trial.
