If a comedian elicits a laugh from a person - who is at fault if the person laughs, the comedian or the person?
I would argue that the person is at fault. Unless you are suggesting one does not have a choice whether to laugh or not.
If that were true, then all comedians would either be funny, or not funny, for all people. That is simply not the case.
Fault doesn't really have anything to do with the original assertion. In any case, that's a pretty weird take on comedy. When you hear a joke, do you ponder it, decide to interpret it as funny, and then deliberately choose to laugh?
Imagine even entertaining the idea that laughter is a bad thing.
Nonsense. You are making the assumption that laughing is always voluntary, and only to communicate that you find something amusing. Both parts of that are false - for example many people will laugh instinctively as part of a fight flight response when the perceive danger from others to communicate "hey im with you and not scared, don't hurt me more". People who hate veing tickled because they feel defenseless will still laugh when tickled, for one concrete specific.