The problem with a situation like you're mentioning is that of correlation vs causation. Many times we like to say that since there is a correlation, it proves causation. Like you said, since more violent people tend to enjoy GTA, people will feel that GTA causes people to become violent. But that's not the case. Many people who are very peaceful will enjoy GTA.

So there is a correlation between a societal view that portrays women on beer commercials as always being party girls and rapists views as not seeing them as real people. But those commercials aren't the cause. There are millions of men that can watch that commercial and not see women as objects. It is merely a correlation between the twisted view of a rapist and a societal view of girls who drink being nothing but party girls.

I hope that makes sense, I think I confused myself ...