Why don't I get to make moral decisions for the public?

Taking a break from my poetry class, I will practice my ranting a bit. 

Recently, someone told me I was judgmental because I did not think playing video games where you shoot your family (as other characters in the game) was healthy quality time.  It is an opinion.  I am not saying these people are bad or immoral.   I even took part in such games at one point in my life (what else do you do when trying to stay awake between a midnight shoot and a 3 a.m. edit lab in film school?). 

However, if I were to be, let's say, a cashier at K-mart (which I once was for a brief time), and I refused to sell any copies of Grand Theft Auto III, which allows the user to have sex with prostitutes then kill them (or something close to that order), because I think it is morally corrupt, I think I would likely be fired or at least reprimanded and considered uncooperative.  Yet, it is alright for a pharmacist to refuse to sell Plan B (an intense dosage of the same medicine used in birth control pills to prevent -- not end -- pregnancy in the event that Plan A -- such as condoms-- fail) because he/she feels it is morally wrong.  Morally wrong?  To make sure something I don't want to happen to my body does not happen?  Yet, it is alright for me to buy a video game for my teenager that, in my opinion, teaches him/her that aggression can be entertaining and that it is alright at times to disrespect women (though defenders of the game say that points are taken away for the sex-kill option yet) that MAY lead to real life aggression in sexual relations, perhaps pressuring girls into unprotected, maybe even unwanted sex (though I do not mean to imply that girls never want sex, but maybe not with icky boys/men who play overly violent video games) who may then need, but not be able to buy, Plan B.   

Ok, so maybe that is a bit judgmental.  However, my point is not to take down Grand Theft Auto; I don't think Grand Theft Auto has that much power, though it  does not seem to have any redeeming value either.  However, I doubt that being denied a copy of Grand Theft Auto would adversely effect the future of young men in the same way that being denied Plan B or abortion could adversely effect the future of a young woman.  Beside, I am not out advocating for banning anything, not even Grand Theft Auto.  Or SUV's.  But that's another rant, which I think gas prices will probably make obsolete soon.