The joke that needs a powerless target has borrowed its ease from someone else.

Some laughter is paid for by a person who is not in the room. A joke that only works because its subject cannot answer back is not really wit; it is borrowing safety, and the ease everyone feels is the ease of knowing no one will be corrected. The same line aimed at someone able to reply would have to be much better to land.

A reasonable test is to ask who bears the cost of the laugh. If the answer is the person with the least standing to object, let it go by unrepeated. Silence at that moment is noticed more than you think.