Yes I've seen that thread and I've stated my gender in it (male).
However I can't see anything wrong with having a gender display option on our posts. Besides for one thing no gender thread could solve the problem so simply.
Not everybody would find the thread to contribute to or refer to in a hurry necessarily. And some may not even bother with it so it may slowly disappear from the immediate pages as other threads came to be used.
So I would gladly support this idea for one.