You have every right to restrict what your child can play and purchase. You have no right to restrict what other people's children can purchase based on the ratings of an unelected MPAA ratings group in Hollywood.
So it would seem that this California law could yet fly in a new version that permits parental or guardian explicit bypass?
Oh so now children can also buy porn I guess by your standards. We might as well live in a dictatorship if we are not allowed to have representation in the making of laws to reflect public decency.