As zhihau has intimated, you are being deliberately blind. Nude men come in every other photo. You just choose to deny it so as to find an excuse to behave like a gay brat and pollute this glorious, magnificent thread.
Just curious the risk of a vaginal infection must be really big considering that their are sitting their bare asses on unprotected bike seats. Also is there a risk of cross contamination as in stuff from the vagina gets left on the seat and someone else sits on it. Obviously not everyone rides that bike solely by him/herself they do share those bikes.