You'd be amazed how many people don't even know the word vulva exists. "Pussy" is an all-inclusive slang term, and vagina refers to the part that most people seem to care about most. They know the clitoris is there at the top and don't give a shit about the rest...yeah, it's not terribly sensitive, but it's THERE. In fact, the only time I EVER remember hearing the word "vulva" outside of a medical or feminist setting was in Look Who's Talking. Isn't that pathetic?