Shouldn't you be more concerned about how videogames normalize violence? There's much more violence in games than "sexism", yet no one seems to be concerned about that.
Could it be because we know that violence in games does not translate to violence in real life? If you agree with that, then why do you have so much trouble agreeing that "sexism" in games does not translate to sexism in real life?
What part of 'videogames are not real' do you and other tumblr feminists not understand?
A couple of reasons off the top of my head:
1. Objectification is more avoidable than violence. Unlike objectification, there are actual design reasons favoring violence as a game mechanic (TL;DR version; video games are by and large spatial simulations, and it's much easier to represent a gunfight in space than even a simple conversation).
2. The entry barrier for sexism is a lot lower than it is for violence. When you engage in violent activity in real life, you incur a substantial risk of repercussions onto yourself; this risk is enough to prevent most people from beating the crap out of each other. By contrast, it's a lot easier to get away with sexism. Heck a lot of racism and sexism occurs at a subconscious level, as the growing literature on implicit bias will attest to.
Having said that, the real world consequences of racist and sexist tropes were never the most important part of that conversation for me. Even if I could prove that horribly written video game dialogue has no negative effects on verbal intelligence, or that that notorious episode of Law and Order: SVU had no negative impact on the general perception of gamers, that wouldn't thereby immunize such works from criticism. Rather, it seems that these are just bad artistic choices independently of the social consequences, and perhaps we can say the same about the inclusion of objectifying imagery when it isn't story or theme-appropriate as well.
EDIT: Fixed typo.