Not having read his opinions on this subject, I did a search under "Doug Giles bus monitor". The reference I found to prison rape was "these little devils would have justly been hauled to juvey court facing a five-year lockdown and jail sex." I could be wrong, but I don't read that as advocacy of the practice, merely a statement that it is a fact of life.
To me, the fact that he used “justly” to describe that outcome indicates approval of five years in prison plus anal rape for pre-teens as a punishment for emotional cruelty.
He didn’t have to bring up sex at all in order to make a point about applying significant consequences for bad behavior: he chose to. I will not further speculate as to why he made that choice.