Hey, I won't say don't worry about it, but let me explain to you the idea behind stereotyping people in a condescending way.
Many people that do this kind of thing feel inferior and weak because they have no argument to stand on. They are mentally unstable, due to various factors, and take the easy road and put others down for aspects of themselves they either cannot change, or should not change. The truth is women can kick my ass in most video games. I'm a guy, but I have seen through experience that male or female shows absolutely no cognitive difference in terms of how we play the game. Guys that do this aren't actually trying to actively insult you to hurt you as their only goal. They need something to step on in their moments of failure because they are weak emotionally.
I'm not making excuses for these people or invalidating how you feel. I just want you to know possible reasons that are not related to you at all may be contributing to your issues. I want you to know that I care and think about how this affects women. And the sad thing is, they're shooting themselves in the foot. I for one would love it if more women played video games, so I could meet them online and maybe become friends and find my partner through an associated network. I can't imagine a world in which these guys would act this way towards women and not expect to be single for a very long time.
So really, it all amounts to stupidity and immaturity. I am sorry you have to take our immaturity, but know that in the end, you'll come out ahead of them because you don't need to put someone down for something outside of their control to make yourself happy.