Do you know what the holocaust victim said when he was getting gassed? Aw, schwitz.
Did you really say that? Are you making fun of people dying?
Yes I am, it's just a joke.
The holocaust was a very traumatic event and the descendants are still bearing scars from it to this day. It's not something to joke around with, as millions of Jews died in those camps. What if your ancestors were killed in such an event, would you like getting joked on about it?
Who cares? It's over. Jews are not being persecuted anymore.
But Jews are still being joked about, and that can be hurtful. They suffered so much when they got sent to Auschwitz and laughing at their pain is awful.