Pope Benedict XVI once wrote an article (I do not have the original source available) describing the true cause of all of the recent sexual abuse scandals in the Church. He said it was not what most people thought; according to him the cause was apostasy. When someone apostatizes from the faith (whether clergyman or layman) they will often try to stay in the Church, but will give in to various types of immorality. They no longer believe in holiness, so they fall in to some of the worst kinds of perversion.
A number of critics at the time spoke against what the Pope said. His response (which is from memory, not an actual quote) is priceless:
My critics have proved my point: they don't get what I said because they too are apostate.
He certainly had a way with words.