Why did I fail my chemistry test? Because apparently Zyklon B is not the correct answer to "what is the most useful chemical for pest control?"
Are you implying that the Jewish people are pests?
You know they're fucking rats.
Zyklon B was a chemical used to exterminate Jews during the Holocaust, and to imply that Jewish people are pests meant to be exterminated is harmful rhetoric. Throughout history, Jewish people have had to contend with being stigmatized simply because of their ethnic background and religious beliefs, and a joke like this just perpetuates that. Instead of harboring negative sentiments about the Jewish people, you should take some time to get to learn about them.