You have to realize that most child abusers were once abused themselves. It's the lucky ones that are able to break the cycle. And, it's more prevalent than you may think. There have been four cases of abuse in one form or another in our family. And it doesn't have to be physical either, it can be emotional or psychological as well. This does not excuse the behavior by any means, I'm just pointing out what a lot of people don't know. I'm married to a child abuse victim so I know a little bit about this. Another thing people don't know much about is how this affects the victims future relationships. I won't go into details but it does.
The recitivism rate for sexual offenders is somewhere between 80-90%, more than any other type of crime. Why? I think it goes back to a handful of factors. The act of sexual abuse is almost never about sex, it's more about control. It's about intimidation as well as sexual gratification. The sad part is and always has been that it's rarely reported because the victims feel ashamed or afraid of the offender.
What do we do? Keep our eyes and ears open. Some vocations are required by law to report suspected child abuse cases. Schools, doctors, daycares, several others. The biggest problem you run into there is denial by the family, anger, sometimes violent reactions to the accusations. It breaks up families which is another threat used on the victim.
There are no easy answers. Severe punishment threats won't stop these offenders in most cases because it's not something a child abuser thinks about from a behavior standpoint. The urges are stronger than most other behavior type urges. What will help is keeping an abuser behind bars longer and using mandatory chemical castration. In the case of the guy in Vermont, there's a special place in Hell for those animals.