That's curious given your background. I know a couple of people that still have the tattoos on their arms and one guy who literally has no family at all and it pains me to see that people think that this is just a matter of bad taste. "Gas the Jews" is not a joke, my sense of humor is pretty broad but it does not stretch that far.
I can't even count the number of comedy central stand-up specials I've seen that casually make jokes about absolutely horrific things that destroy lives. Jokes that play on children dying, slavery, the holocaust, rape, murder, pedophilia, torture, etc. I guarantee you that both you and I both know someone (or are one person removed, at most) that has had their lives destroyed by one of these things, or something of a similar caliber. Does that mean that none if these jokes can be funny, in any context? If so, I'd say you'd be hard pressed to find a single comedy special that counts as funny; virtually every comedy special I've seen makes light of one of these horrific things in some way.