Seems to be working just fine in the Czech Republic, and from reasearching a bit it seems as if other countries are considering adopting it as a practice....your argument against castration and the death penalty is more morality based then data driven. Simply, the US has not adopted this practice so no real data is present because no studies have been done. Articles written about the veracity of this as a detterent seem to be mostly OP ED pieces written by folks that speak to the morality of castration, and apply meaningless opinions to support their belief that it is wrong. I say try it, take a study where you surgically castrate half of the study and chemically castrate the other half and see what the results are. As far as women pedi's, I don't have a solution for them, I am more concerned about the men because they represent as you said the larger portion of this population
First of all lets define terms here so we are on the same page. There are two kinds of castration being discussed, surgical and chemical. Surgical is removal of sex organs while chemical castration is the administration of drugs such as with Depo-Provera, cyproterone, or Benperiodal. The medication, depa-provera, is injected every three months and reduces sex drive, ability to be aroused, and sexual fantasies. The effect of the first two drugs is similar to receiving female hormones while the third one is an anti-psychotic. Chemical castration is reversible to an extent while surgical is not.
There are a few states which do allow chemical castration in the case of repeated child molestation including California, Florida, and most recently Louisiana. As for the death penalty, the Supreme Court ruled in 2008 that killing child rapists where the victim was not killed was unconstitutional.
The deterrent component is not fear of offending because you will be castrated but reducing desire and fantasies through drugs which counter the impulses in chemical castration. Obviously surgical castration reduces hormone production permanently essentially making them a eunuch.
Here is a good discussion: