My mother was never like that. She's an ex hippie that lived on a commune till her first husband died from cancer, and later she met my dad blah blah blah there. But her and dad did made me just play Mario games and such. They would keep me away from obviously violent games like Mortal Combat.
nowadays it's popular for people to play as the bad guy in games with moral choices...just for something different. I do play a gun crazy wasteland raider in Fallout 3, and an evil mage in Oblivion. Not evil in real life, but something to explore in fiction. Ironically to know good, one has to also know what's evil too.