It seems to me that you guys are more or less talking past one another because one's response is formulated from a different paradigm than what it being responded too.
Criminal justice is about just that, JUSTICE! God has given it to the governing official to enforce justice - not vengeance (not in the sense that the word is commonly used, anyway). The difference being that the later is performed emotionally, even arbitrarily, where the later is performed dispassionately and with clear intention after the facts have been clearly established before a disinterested third party (i.e. a judge with no conflicts of interest). The point being there, not that vengeance is evil per se but simply that if we are permitted to take vengeance, we'll screw it up and innocent people will be getting murdered, which would counter productive and lead to more death, not less.
As for the method of punishment, the government could very well decide to collect a bunch of CONVICTED pedophiles into a condemned building and blow it up with the convicted criminals inside. It could just as easily run them all off of a cliff. The bible does not condone torture but short of that, whatever works!
The problem with the idea of a mass execution of pedophiles is that in a society that actually executed those who had been convicted of such crimes, there wouldn't be enough pedophiles around to fill a building with them. The hypothetical could only ever exist within a society that would never execute a pedophile at all. A society that starts putting pedophiles on trial and quickly executing those convicted of the crime would very quickly find itself free of not only pedophiles but of homosexuals in general. They would either all leave to find a more tolerant (of evil) society to live in or they'd stop committing their sexual crimes.