Beats me. I'm by nature an unforgiving person, I remember slights and fights and hold grudges forever. I really think the only person I've ever forgiven for anything is my wife.
A pederast? Unless s/he was like abducted by Neo-Nazis and "had to" do this for the greater good ("rape one or kill all"), or rendered insane by a blow to the head, some neurotoxic agent or mental degenerative / hallucinatory disorder.... I can't even imagine forgiving them.
"Don't think it hasn't been a little slice of Heaven just because it hasn't!" --Bugs Bunny