How do you get a nun pregnant? Dress her up as an altar boy.
why would you say that about nuns and alter boys?
It's a joke. I'm sure you can find the humor.
Even if something is true in the past, that doesn't mean it should be joked about. Joking about Christians abusing children in front of others could offend or upset people, plus it makes you look somewhat creepy so if you value your relationships, you should stop doing that.
Don't be so sensitive.
I wasn't the one making bad jokes. A lot of people share the Christian faith and they probably find that really offensive. We should be tolerant of those who are different from us.