The recidivism rate of child sex offenders is off the charts. Some state legislators floated these very drugs as court-ordered “chemical castration”. However, this solution was beaten down by feelgood leftists as being too cruel of a punishment for child rapists.
A more feelgood punishment for them is to be beaten to death by the child's family. But if you're not in favor of the death penalty, see my FReeper profile for a proposed alternative...