 Could he stop it? Yes, he could. Does he allow it? Yes, he does. Why does he allow it? Well, for example, if God did not give you and me the freedom of choice, if he'd created Adam and Eve without a freedom of choice, they would have been like robots. That is, living amidst the Garden of Eden and just doing one thing, one way, not because they wanted to, not because they love him or not love him, because they would be almost emotionless. That is, no choice.