Judging by some of the comments, I may have over-edited Donald's email in this post. He wasn't speaking of humor in general so much as of telling jokes. (Telling jokes and laughing at them is a big part of humor, but far from all there is to it.)
More from Donald's email:
Let me explain how jokes work (simply and some of this is controversial, as there are different theories of humor): essentially, a set-up establishes a context with a system of belief points. The punchline states a word or phrase which is consistent with the possible belief points in one sense, but not another. The statement of the punchline causes a "crisis in belief" in that two, apparently contradictory truth claims must be believed. Obviously, the rational mind cannot handle this and would, ordinarily, reject one of the claims or deny the communicative structure of the story (i.e., it is non sequitur). There is, however, a very large class of such dual belief activators (punchlines) in which it is possible to "project out" one of the beliefs into an alternate possible universe (a counterfactual universe) which could exist, "just in case". I am using terms like, "belief points", rather than, "attribute sets," because I want to, eventually, link the discussion to issues of Faith and Hope. For instance:
Did you hear the one about the guy who fell into a vat of gum at work? The boss chewed him out...
Now, the belief points are: 1)boss = traditional human being, and, 2)chew out = to yell at. The punchline, however, presents a case where, apparently, the boss actually could have extricated the worker or yelled at him. One has therefore, a chimerical boss: one who, apparently, has a normal set of teeth, and one where the boss has a very strong, large set of teeth. Both cannot be simultaneously right in the same possible world, but they can exist in two different worlds that the imagination is able to cross between. Thus, the mind oscillates between:
chew out (world 1) = to yell at chew out (world 2) = to extricate by mastication
We accept world 1 as the correct world matching our world of experience, but we cannot completely discard world 2 because the context will not allow us to exclude it. Thus, we have an oscillation between a "real" world and an "imaginary" world as a way of circumventing the Law of Non-Contradiction by projecting out the incongruity into an alternate possible world which accepts a truth claim from the original context of the joke. Humor theorists call this, "script switching as a way of resolving an incongruity."
To the extent this is "how jokes work," there are jokes that Jesus would not find funny that His disciples would -- and vice versa, I suspect -- because, being Divine and sharing in His Father's power, He has a different set of "belief points."
I don't know, though, whether not finding it funny is a moral impediment to telling a joke the audience would find funny. I tell unfunny jokes to my children, expecting they will laugh. Sometimes I tell unfunny jokes to my children, expecting them to laugh at how unfunny the jokes are. I suppose that moves the incongruity to be resolved from the joke itself to the telling of it.