Most Helpful Girl
Multitude of reasons.
Some women are conditioned not to approach men.
Women are told they are desperate/thirsty if they approach a guy.
Some women have social anxiety and don't approach anyone.
Some women my believe that men they find attractive are already taken.
Some women may find him attractive, but not attractive enough to go after him.
Some women may not be in the mood to socialize that day.
Some women may have a fear of rejection.
Some women may think that you are gay.