Part of how we love other people is not to make them the butt of our jokes. If you could see how much your humor sometimes hurts other people, you would be slow to repeat some of the jokes you hear. Why would you hurt someone else for the sake of a momentary laugh? That is not a loving thing to do, is it?
I remember telling a joke a long time ago that mocked a certain category of people. The man I told the joke to didn't laugh. He didn't reprimand me. He just didn't laugh. His non-participation in my buffoonery was a powerful lesson to me.
Never tell a joke that mocks any group of people. And don't laugh at their jokes either.