Why is the topic of child sexual abuse so important to Dostoevsky?

Crime and Punishment we have Svidrigailov. We have Totsky in Idiot . In Demons we have Stavrogin. And in The Brothers Karamazov we have Fyodor Pavlovich who raped a girl who was insane and did not understand what was being done to her. I know that there is a rumor that Dostoevsky himself was a pedophile, although I doubt its veracity and think that it is most likely not true.