Danny Sichel messaged me to say:
The backstory to Nunsense is that a large group of nuns die of food poisoning. Food poisoning is not a comfortable death. Are we supposed to imagine, when attending this hit off-Broadway comedy, the previous group of nuns screaming in agony as they shit out their intestines?
Of course, Futurama used the same basic setup as regards the Planet Express crew prior to Fry, Leela and Bender. But they are cartoons, so the horrible deaths are more permissible, I suppose.