Many cases seem to come from boarding schools or schools for handicapped children. In these situations teachers have more power over their students than usually, hence the greater likelihood for abuse (and the greater need for control, who watched the watchers).
I also think that church-specific factors like the good image of priests (OK, that is undone now) as well as celibacy have an influence but just a mild one.
So besides the obvious guilt of the abusers, who is responsible for the mess? Parents who didn't teach their children to be critical of any authority or parents who didn't care what happens to their children in the boarding school as well as the corps climate among the teachers in the school. The latter is not limited to schools, just take a look at police violence and the lack of willingness of the police to reveal the foul apples.
As kids nobody liked the fellow who told tales about someone else and as adults this means covering up the abusers among your colleagues.