Lama ragashu goyim, seems to apply equally to the frum here too.
Ergo: Humour based on the human condition...
David's Bar mitzvah. Whole family gathered together. Everyone happy, except old uncle Issaac.
"Issac, what's the matter"
"Nobody cares about the Jews"
"Issac, what's brought this on? you've got your whole family here. At least cheer up for the boy!"
"Nobody cares...you know, during the war, the Germans murdered 6 million Jews, 4 million poles, 2 million communists and 28 postmen."
"you see. Nobody cares about the Jews!"