Maybe it is a little more complicated.
In the catholic church there are a lot of "Holy Mary" whorshippers who consider her to be warm, forgiving, "pure", i.e an asexual mother figure.
These are the same people having extreme troubles to integrate an adult version of sexuality into their personality, i.e to start seeing women as sexual beings.
So if someone like that approaches boys that are approximately at the stage of sexual developement that he cannot grow out off, he probably seeks himself in the boys he targets.
He is also terrified of the idea of actually penetrating a grown woman, because that would mean seeing themselves as aggressors, sexual agressors, no less, and that is something they simply cannot do. Of course by not being able of seeing themselves as aggressors they actually become it in a truly twisted, i.e. perverted kind of way.
Of course what they do are homosexual acts but
A: their inner game is very different from that of a grown-up homosexual
B: from a practical point of view they have more in common with heterosexual pedophiles.
If they were banging 16-17 year old altar boys I would not have any problems with it, because that would be a homosexual who has a problem I can relate to, i.e. he does not know how to keep his dick in his pants.