I recall my father and others who served in WWII looking forward to Hogan's Heroes each week. They were laughing at jokes and scripts about the SS and the Gestapo - certainly two groups which caused untold grief and tragedy - and enjoyed it immensely because the writers were making fun of some monstrous people, but people who had murdered millions.
Good humor is best when it has a basis in truth - whatever that truth is including darker subjects.
I remember a joke going around after the Challenger disaster..."No! I said a Bud Light!" Sorry, but it was funny.
On topic - I read today that an allegation has surfaced (ahem) about the helmsman on the Titanic having a mental disconnect on whether to turn left or right and he chose wrong. When I was in the Marines, when someone turned in the opposite direction from what was ordered, we'd often chastise them with "No! Your military left (or right)!"