You missing the biggest point glaring you in the face. The fact is, guys actually have to WORK to find a girl. Girls, unless you are horrendously ugly, can snap their fingers and get laid.

A girl can go out and ask almost any guy she wants if they want to have sex and most would probably agree, or a least politely say no. If a guy did that, all that would happen would be that he'd get slapped by a shit ton of girls.

The problem here is all about manliness. Men are taught since childhood they have to struggle for what they want. So a woman that say NO is just perceived as challenge rather than as a person. No woman is expected to say yes without some special effort that will prove to the male of how great he is (more to himself than to her thought).