Does self-deprecating humor damage one's self-esteem?

There is an illuminating section on "Humor and Morality" in Ayn Rand Answers, pp. 140-142. The opening question, asked during the 1976 "Philosophy of Objectivism" lectures by Leonard Peikoff (Lecture 11), received a lengthy reply by Ayn Rand. The way the question was worded caused Ayn Rand to classify it as a dishonest question, and her answer explains why. In the process, she offers some very useful insights on the nature of humor. Here are a few examples:

Humor is the denial of metaphysical importance to that which you laugh at.... humor is destructive, which is proper [depending on the target of it], but its value and morality depend on what you're laughing at. If you're laughing at the evil in the world -- provided you take it seriously but occasionally permit yourself to laugh at it -- that's fine. But if you laugh at the good -- at heroes, at values, and above all, at yourself -- you are a monster.

Whenever I hear someone say there is no humor in my novels or heroes, this is what is meant. There are funny passages in all my books that I know have caused readers to laugh out loud. But there isn't one line that laughs at my heroes, my values, or anything good....

[Humor in a play like Cyrano de Bergerac] is always directed at human weakness or evil, never at Cyrano himself.

The worst evil you can do, psychologically, is to laugh at yourself. That means spitting in your own face.

Regarding those who strive to make humor a "major part" of their lives and want others to do so, too, Ayn Rand explains:

Anyone looking for humor as a major issue is looking for that [laughing at oneself]. Such a person doesn't think it's funny when you laugh at him -- that is, at villains -- but he wants you to laugh at yourself, and will be happy and at home only with another character like himself, spitting in his own face.

From these comments, I see the issue of self-deprecating humor as wider than just self-esteem, although dimished self-esteem certainly seems to name the essence of the psychological harm, and probably helps to drive future acts of self-deprecating humor as an escape from personal responsibility for living and an invitation for sympathy and companionship from other similar sufferers of low self-esteem.

I think it depends a lot on how the humor is done. If a comedian is truly making fun of themselves, that's probably unhealthy. But many comics just temporarily pretend to be a certain way, or they exaggerate some feature or stereotype, and then make fun of that. In most cases, I don't think that's damaging to one's self-esteem. In fact, being able to get a laugh out of a crowd is probably a good builder of self-esteem.