If that's the case, then that's wrong -- and it hurts the tech community at large for it to be that way.
This is a witch hunt. It may be a witch hunt for good reasons, and for a cause I support (which I do), but let's get it clear: people are protesting because somebody has a job that has opinions they don't like. That's not a healthy attitude for any community and any job.
I don't care if the man's a nazi. We live in a free country where diversity of opinion, problem-solving skills, and life experiences are invaluable for creative and productive team performance. This kind of thing is horrible and detestable, no matter what the man thinks in private.
If he's a criminal, fire him. If he proposes some policy that is bad for his company, fire him. If he has some personality defect that is bringing harm to Mozilla's name, fire him.
Otherwise? Leave him alone and let him do his job.