Why is that such a horrible word for guys?
To emasculate him. It's an insult to say a guy is doing something like a woman. There's nothing wrong with crying or being submissive and weak... as long as it's a woman doing it. There's nothing wrong with finding a male really attractive... as long as it's a woman doing it.
So a guy has to be careful. He doesn't want to look like or be called a woman. He definitely doesn't want someone to think he's gay. We may not realize how much we are aware of this, but it's underneath everything that we do. How we walk, how we talk, what we do, even which ear we pierce.
It has plenty to do with how we view women and how we behave in relationships with them. It has everything to do with how we act towards male friends and what we make of our friendships and our feelings for other guys.