Regardless of whether the person who wrote that should be fired, calling that post "hate speech" demonstrates a pretty fundamental misunderstanding of what hate speech is. It is not merely exclusionary speech, and it is not merely speech that singles out particular groups - only protected groups. Holding particular political views - no matter how popular or right they might be, and no matter how persecuted you may feel for holding them - does not qualify you as belonging to a protected group.
If you want to fire this person, fire them for misrepresenting the Mozilla organization in a public forum. Stating that the tech industry will be better off without feminists - while a pretty stupid opinion to have - is not even remotely "hate speech", and while it might make Chris Beard feel a little more righteous to call it that, it does not reflect well on his capacity for rational thought.