That's still OK with me. Twitter might not be a private space, but his opinion is his own to broadcast in his Twitter stream.
As long as he doesn't attribute this opinion to the project or anything.
>If you are a high-profile member of a project, the fact that the space doesn't have the project logo on it doesn't necessarily mean people aren't going to look at what you say and connect it back to the project.
Even if it means that, they shouldn't (connect what one person says with the project). What if it was his political or religious opinions? Shouldn't he be able to say he is an atheist / democract / devout / republican whatever in his Twitter stream? Post jokes about Obama or Bush, etc? Pro or against the death penalty? Etc.
If that's allowed, then why wouldn't be having an opinion about sexuality (which is another topic people see as political/religious/moral/whatever).
I find that the reason some people ask (and get) people fired from their jobs or thrown out of projects because of their view on such issues, is not because such issues are more clean cut than the others mentioned, but because they can get away with it.
In conservative places they hurt people with progressive opinions, in progresive places they hurt people with conservative opinions. And that's what I dislike the most, people seeing so that active harm happens to others they disagree with (as opposed to those others just stating their opinion). For me that's worse than being a bigot -- it's being a bad human.