I'd say a lot of us are loud and proud. I sort of equate the internet to like a college campus though... Big place, different people. You're going to ultimate end up advertising yourself as part of a certain crowd at some point to find comfortable people.
Same psychology in my book here. You throw on certain things for avatars as an attempt of clique advertisement.
But, those closeted folks are probably out there no doubt. But they're such an outlier it's hard to count them. Probably more so if they don't visit anything like EQD or would be in a loop when an academic survey is being had.