(not fighting, sorry if i sound like a dick) Now that wouldn't make sense now, would it?
If they would rape a little boy because they wanted to get some pussy, then why not go for the pussy? I mean either way they're are doing something "wrong".
Because 'pussy" can fight back, tell the police, and give detailed descriptions of what the alleged attacker did to them. Little children, a) might not know it's wrong for a priest to do that to them b) more likely to make mistakes about describing what happened to them, and c) kids are easier to manipulate (especially when they're told god will kill them and their family if they tell anyone).
To someone as gullible as a kid, telling them a supernatural entity will hurt them is a very real thing.... it's like being told Santa won't come if you're not a good boy/girl. Which is usually fine.... People learn that Santa isn't real, the kids problem is they're surrounded by people that reinforce their beliefs that God is real, and can and will punish them for going against the church.