Maybe your face is just uglier than you think? :)
Just kidding. I have the same experience as a man. I'm no George Clooney, but I have all of my teeth and consider myself to be "average" looking. That said, I get messages from women who are very unattractive to me (morbidly obese is common).
But I can't knock them for it. Maybe the girls that I message are saying the exact same thing about me. Who knows.
The problem is that there's basically nothing to lose by sending someone a message.