I'm saying that nuns would have no reason to greet non-extremist Muslims with guns.
You're bordering on parody now. Pull the politically correct stick out of your ass and laugh and/or move on. The idea is obviously that some sort of muslim terrorist blows himself up thinking he will get to screw young hot virgins in heaven and then is greated with angry old nuns (also virgins) instead. It wouldn't be as fun if there was an asterix explaining which muslims were or were not the target of the joke. Bonus idea for you: All superstitions, including islam, deserve to be made fun of. Do you have a problem with mohammed depictions too?