aphyr is homosexual and isn't afraid to let the world know[1]. I think it is just his own humor. I actually find it pretty hilarious how often he changes his twitter picture and the strange things he switches them to.
It is just a quirk of an incredibly brilliant person, which I personally find hilarious. That being said, he has a great point of view on non-tech things and is a super humble guy. As quoted from the movie Van Wilder, "You shouldn't take life so seriously, you'll never get out alive!"