The guys (well, some of them) are discussing her treatment behind her back. One of them even apologizes every time he swears in a meeting. That means even the ones who care honestly don't know how women want to be treated in a workplace. (Of course, part of the problem is that they are constructing some kind of universal ruleset without considering her as an individual.)

It seems that no one knew which guys were the jerks before because they acted reasonably when women weren't around. I think the same thing happened in tech circles. There are some major assholes and even creepy stalkers that don't really show themselves until women show up, so they go unnoticed for years by the male majority.