No, it doesn't become sexual because it's not in a sexual context. Do you think a heterosexual gynecologist gets a boner every time he sees a patient's vagina? No, because a gynecological exam is not a sexual experience. If I'm going to the gym, I'm going there to work out, not troll for cock. I might see a guy that I find attractive, but I'm not at the gym to look for attractive men. I can't speak for all men, but I don't find the lockerroom to be an erotic setting. Besides, you might not even be my type. If I'm not attracted to you and you're not attracted to me, where's the sexual dynamic?