Toy guns don't turn kids into mass murderers. Author Heather Shumaker says:
Playing with toy weapons will not make a child violent. Respect a child's right to play. . . . War is as legitimate as playing house. When a preschooler says "Bang! Bang!" it's a game, not violence. Don't be fooled because the topic may be violent — this play is typically highly social and cooperative, teaching your child skills in friendship and even early morality. If we fear weapon play and ban it, children may still pursue their fascination with power and weapons — often in places we can't see it.