Because I addressed it earlier in this thread. It's a stupid argument to make. "OMG there are so many things worse so you concentrate on this!?"
No, it's perfectly legitimate considering I doubt people had serious moral expectations from the cliched, sexist action hero archetype who slaps a woman rump while he is slaughtering things wholesale. By design it's either meant to push a boundary or focus on vicarious enjoyment, neither of which degrades videogames as an industry as those same techniques are employed in other entertainment products. Gaming doesn't need to grow up, people do.