Characters are fictional, and fictional things cannot really hurt you. If an RPG character is portrayed as "stupid", usually as a simple caricature, they are just make believe. As long as the players are able to separate reality from make believe, then nobody will take the "stupid" character's behavior seriously.
This is like saying that if you play a Friday the 13th RPG, then you think this actually promotes a guy in a hockey mask killing camp counselors. It's just make believe. It doesn't mean you are pro-murder, pro-hockey mask, pro-maniac, or anti camp counselor. It's only a movie, and respectfully, RPGs are only games we are playing, while eating Cheetos, and drinking Mountain Dew with our friends.