Think about this from the perspective of an abused child. The message is that not only did you suffer, but now you're doomed to become a monster. If someone grows up believing that they are doomed to become what they most hate, that's a pretty big cross to bear. And I suspect that believing this message would make it harder to deal with the problems that result from abuse, and therefore would make the prediction more likely to become a self-fulfilling prophecy.
Even if it doesn't become a self-fulfilling prophecy, it adds a huge burden to children. Particularly since it makes it hard to cope with things that happen to most people. For instance what man has not looked at a woman, thought she was attractive, and then realized that she's jail-bait? If you're fighting the belief that you're a child abuser in the making, this trivial event becomes a confirmation of your worst fears. How are you supposed to cope?
I far prefer focussing on the fact that most abused children do not grow up into abusers. There really is hope, and knowledge that there is a way out bears the possibility of becoming a much better self-fulfilling prophecy. That doesn't mean that we should be Pollyannas (particularly when it comes to protecting our own kids!), but it does suggest a more measured response.
This is even true in the case of children whose abuse pattern included secondary cases of abuse as children. I don't think that someone's actions at 12 when they don't understand what they are doing inevitably predict what they'll do at 24 when they hopefully do understand.
Regards,
Ben