Years ago, when this stuff first started coming out, some priests came forward to say that the reason why they chose the priesthood was b/c they were so ashamed of their desires for other men (in general, not "children", specifically but when they were 18-22 themselves and making this decision those "children" weren't really "children" to them anyway) that they figured the forced celibacy was the only answer for them. It wasn't because they were attracted to children per se, but to other men. Their desire for children was something that developed later out of the strange brew of celibacy, catholocism, guilt, repressed desire, shame, guilt, opportunity, and, sometimes, socialization and good old repetitive fantasy, etc.
They maintained that they ended up unable to control their desires anyway and, given more socialization in the institution itself, as well as more and more opportunity given the situations they find themselves in, as well as their human desire.... combine that with a heavy dose of guilt, shame, self-punishment, etc. I find it quite plausible that these are simply men who were gay, but not especially or necessarily interested in "children" who became so eventually because the extended exposure and opportunity was there.