What happens when you fart in a synagogue? It turns into a Holocaust memorial.
That is quite insensitive. What would prompt you to make a joke like that about the concentration camps?
How do you know what happened in 1939-1945?
I think most people are aware of the tragedies that happened from 1939-1945. Joking about the Holocaust like that is extremely offensive and harmful to Jewish people. They suffered greatly in those years and making light of it makes it possible for it to happen again.
They deserve it ...
Why would you think millions of innocent people deserve such a terrible death? I think it would pay for you to try and educate yourself a little more, to understand how jokes like that are very harmful to victims and survivors.