Jokes are the foot in the door to get the conversation going. Leftists rarely even tolerate this if it's the wrong topic. The right can support their argument if pressed, but the joke is necessary to get people to even give them the time of day, else the left will continue to plug their ears and pretend like there are no consequences for their chosen path. It's not that jokes are bad. The situation is that, as usual, only the left is allowed to use them.