Why? You have to be asking why. And I'll tell you. We as an online community have, for a good portion, become insufferable jackasses.
We have a community of like minded people that we have actively sought out and we act like assholes to each other. We brow beat each other. We insult new players for being new players. We create hostile game environments in which people don't feel welcome. Women, nice kids, and people of varying sexual and gender identities are harassed for wanting to play a game and be apart of a community.
When I play open matches, normally I won't even connect my mic (unless my aforementioned dickish behaviour is happening). It isn't because I feel scared but its that when I want to play a multiplayer game, I don't feel like being told I play well "for a girl" or be informed they will rape me should my playing continue to be at least adequate. I don't want to get called a whore for winning.
I also realise that good natured ribbing among friends or like minded people can seem harsh to an outsider, but this isn't what I'm talking about. I am speaking of deliberate behaviour meant to hurt another person.
With the recent mainstreaming of gaming and nerd culture, I have seen things improving. I have wonderful, fun, witty online friends I play with frequently. Both men and women, who's gender identity and sexuality I have never inquired about.
And as I said, I am not free of these crimes. I have been insulting and mean to new or less skilled players because I didn't win a match or they picked up the ammo I needed. This is why I'm being critical right now. I'm part of the problem. And you know what the sad part is? Its just a game, a game specifically designed and slaved over to be fun.