This is problematic because it assumes anyone, in this instance any Catholic, attempting to engage in the debate tacitly supports pedophilia - they have to 'prove' they don't. It's a fucked up way to approach an argument, and not substantively different from saying to a Muslim "prove to me you're not a terrorist."
The functional difference being that a Catholic is, by definition, part of the Catholic church (although a Muslim, by definition, participates in zakat, which can have the same end result of supporting organizational structures the follower wouldn't otherwise choose to support). A better way to preface the debate is, I think, to ask whether or not a Catholic feels comfortable supporting the Church with Ratzinger as the Pope. But it's got to be a lot more nuanced than "You support the Church, therefore you support Pedophiles."
I can see where you bristle at what I'm saying, I really can. But let me break it down further. I'm talking about having semi-specific conversations with someone who is defending their religion in light of this particular heinous issue. I have to take issue when you characterize what I said as "you support the church, therefore you support pedophiles". That's not true. What I'm saying is that can't take anyone seriously who thinks that those priests who engage in pedophilia should be allowed anywhere near children in any way, shape, or form. There are probably more nuanced ways of getting at that information...and it could certainly be done in a more deft and polite manner than what I suggested, but that's the core of it. Once we can get past that, I'm willing to talk about infallibility, church heirarchy, whether the act is a sin or a crime...whatever.
So while I think that anger and frustration may be getting the better of my manners, I'm very comfortable with the core of my point. I'm perfectly willing to listen to anything you have to say in defense of your religion if we can agree that old men should not be raping little boys. Or to put it more politely, "Do you think that the priests in question, those who have engaged in sex with children against their will, should remain in any position where they have contact with, and authority over, children?". If the answer is no, then we can move on and argue until the cows come home. If not, then it's no use talking to you for any number of possible reasons.
I'll reiterate the statement that I'm defending here: