No.
Are you homosexual? Go ahead and dance with a person of the opposite gender. Go ahead and chat and be friendly.
Are you straight? Lots of straight boys dance with other boys, and lots of straight girls dance with other girls.
I'd much prefer to identify another player by her name, not by her sexuality. When you make the acquaintance of a new friend, your preference will be divulged in the normal course of getting acquainted. It's actually less fulfilling to learn about the new friend by clicking on a menu option than by the slower and more demanding process of having a conversation.
Another important consideration, a woman with “heterosexual” on her profile might, in fact, be seduced by another woman. (And, incidentally, she might find it to be a lovely and exciting experience!)
Finally, there are quite a few transsexuals in here. Suppose one identifies as being “heterosexual”? What the hell does that even mean!
So, thanks but I prefer to divulge my sexuality the old-fashioned way, not the lazy way.