Pulling punchlines: Comedy can be offensive. But should it be reined in?

Stand-up comic Dan Crohn is telling a joke about the first time he flew Spirit Airlines. It’s Comedy Tuesday at Night Shift Brewing in Everett, Massachusetts. Standing on a spotlit stage, Mr. Crohn forms a wishbone with his arms – elbows lifted high and hands pressed together – as he holds the microphone. 

“Imagine the Maury Povich show at 31,000 feet,” riffs the comedian. “The flight attendant comes up to me, and she’s like, ‘Got any food?’”

Mr. Crohn’s subject matter is fairly innocuous. Well, apart from an oceanic joke about cuttlefish...