I had thought the same thing, actually, but the reality is we'll never know how many of them are AD -- unless a big shitstorm happens and there's a story in the Navy Times or some other AD publication. And then at that point, the little turdburglars that ARE AD get to deal with that issue with their chain of command for demonstrating on a political issue while representing (at least in a manner of speaking) their respective service.
I think there's a good chance that more than a couple of them are AD. Some of the haircuts are a little longish, but apart from that, they're all young enough. 
One of the reasons I didn't think they were, is because there was too much similarity in the shirts....like someone raided a shop and bought all that they could and handed them out.
Another, when T was in, they were supposed to be a apolitical as possible, and stay out of "public" type situations that would call attention to themselves or the military. Maybe it was different in the Seattle area...they aren't too fond of the military up there.

Why would a gay AD risk getting into trouble for this? I would think they already have enough to deal with at work, especially when their work is really 24/7 as opposed to a 40 hour work week in a job that no one cares about one's sexual orientation.