How do you get a nun pregnant? Dress her up as an altar boy
Do you think it is okay for nuns to be raped?
Well, see, messing with nuns is all right and that's why priests like to attack them. I'm in no position to deny that it happens.
It is hurtful for people to joke about sexual assault since it might trigger somebody who has been sexually assaulted. You wouldn't want people to make light of people assaulting somebody sexually if  you had been assaulted.