http://www.alternet.org/story/146920/what's_really_behind_the_catholic_church's_sexual_abuse_problem
the availability of an outlet through pederasty and pedophilia becomes attractive, since the entire institution is geared to hide it and perpetuate it.
...the church takes extraordinary steps to hide the condition, not expunge it. The reason is because it is so ingrained in the religion, for 2,000 years
From my experience these two tidbits seem key to the issue. I grew up in the Chicago area and went to public schools, but within a half a mile from my house, there were two Catholic schools Grades 1-12, and a large proportion of my friends from the local neighborhood were Catholic and attended these schools.
On a number occasions during my upper elementary years, my Catholic friends would joke about priests having sex with boys. None of them seemed alarmed by this, and I took it more or less as humor. None of my friends admitted to being molested themselves, and the jokes were always about priests and nameless other young participants. At that age, they would not have seen it as highly deviant behavior, and were probably not familiar with the word "molested". If you grow up with it as part of your culture, it's going to seem normal, although possibly a bit odd, the kind of thing one might joke about.
There was something about the humor that puzzled me. Why jokes about priests, but not public school teachers? Why were the jokes a common part of their culture, but not mine? While this may or may not be explained by rampant sexual abuse imbedded in the culture of Catholicism, in the end, the jokes proved to be related to something that was actually happening, and no doubt in the Chicago area.
As powerful as he Church is/was, it would be hard to hide an atrocity like this for 2000 years, but it would be easy to let it slide, if not outright ignore it. Indeed, the Church did in fact do just that. My guess is that my friends knew it was part of the culture, and their parents probably did also, but were "letting it slide." Perhaps not ignoring it outright but convincing themselves that the abuse was mostly rumor, and that actual events were rare.
In retrospect, I look back now and believe the abuse had been ignored as a crime, because while not openly embraced by the flock, it was tolerated and ignored, giving the Church a great opportunity to ignore the problem at an administrative level. When society changed, along with these accusations becoming proven, the Church was caught short, and found themselves in a new environment over which they had lost control. No doubt this caused a scramble at damage control in the Vatican, but most of the energy was consumed by the scramble, which for a change, could no longer result in control.
It's the way the Church has constantly dealt with reality. The Earth remained at the center of the universe, until that dogma was removed from the authority of the Church by outside forces. In other words, the Church is not self correcting. It is only corrected by pressure from outside when the church is dragged kicking and screaming into admitting they are in error. It's energy is directed at preserving it's status, not in growth, and as such, it is a brake on progress.