Some thoughts:[edit source]
There are cultural aspects to humor, and an assumed underlying body of knowledge. For example, Jon Stewart does well with an audience with an interest in politics - I don't understand a lot of what passes for humor on Comedy Central (or in The New Yorker, for that matter!) because I don't get the cultural references. Then, of course, there is engineer humor (J) Liz Donnelly touches on this in her TED talk, perhaps you could amplify a little in your text. Some humor doesn't "translate" from language to language. Then there is the humor without words - mimes, clowns, cartoons, posters - which can transcend culture. (an opportunity for peacemaking?) Political humorists have suffered for their art - the Smothers Brothers and (oh, crud, that guy in the '50's...) - but advanced change.
Laughter has been referred to as Internal Jogging. It releases good chemicals in the body.
It has been said that "in jokes" reveal intimacy or social connection.
An assignment preparatory to understanding whether you have a healthy (virtuous?) sense of humor or are mean would be to collect the jokes/situations you find funny and identify the commonalities - racial, sexist, etc. (You've sort of got that, but its not explicit)
Have you run across any exercises to improve one's sense of humor? Peter McGraw sort of approaches it. (i liked his theory, btw - I read the link to theories of humor - interesting - maybe you could incorporate a little of this into your text, just that we don't really understand what makes things funny, and there are lots of attempts to explain) Do you think people are born funny (with this virtue) or can it be developed? Do you think the culture shapes what passes for humor (so much that's out there disgusts me or just isn't funny to me)? Or the humorists shape the culture? (situation comedy has convinced us that dads are all idiots) --- From DB