The real issue is that the Mozilla board saw this coming, and didn't think it mattered to upset a big chunk of the community. That is hubris, plain and simple.
When your organization is dedicated to community, you can't put community second in your decision-making process. The decision made the Mozilla board look out of touch with their mission.
Following this line of thinking, you can see how even an ardent opponent of gay marriage could be upset by Brendan's appointment, purely on the basis that risking the community is the last thing they should do. I wish more of this discussion would be about the Mozilla board's tone deaf decision, and less grandstanding about politics or freedom of speech.