Violence, sexism, and morals are taught to us by our role models. My role models were my parents, hulk hogan, conan, batman, and other 80s stuff like rodger rabbit. I was not influenced by joker, darth vader, freddy kruger, jason vorhees or ronald reagan.
I think this applies to modern video games and children who grow up with them. Yes games are an influence if the child finds a role model in the story. Luckily games which contain story are always given a hero. Except grand theft auto. I met a five year old that recognized the gta iv disc at my house then instantly and gleefully shouted "THE BADGUY GAME!!". I let him play red dead instead because 1. John Marshton is a good role model. 2. Kids can distinguish fantasy role play and life like reality.
my point can be summed up like this.. fantasy role models only. It takes active parenting.