If you are a young guy given the responsibility of coaching a university women's basketball team, I'll bet all parties involved understood the requirement that said young guy keep his pants zipped. It's an absolute no-brainer. That he did not is wrong for multiple reasons: it violates a very important trust between coach and player, one similar to the relationship between teacher and student; there is a huge imbalance of power between the two parties involved; it could create serious problems on the team; it most certainly calls into question the people who hired that guy, fairly or not; and it is morally dodgy as hell. It's not like they are two students who met in class.
I said it was unprofessional. People are acting like he assaulted someone.