That's your definition of comedy. Comedy isn't just some kind of tool to only make fun of the upper class. You must be thinking of cabaret artists.

It can be used to even give the less fortunate something to laugh about regarding themselves. Nobody and nothing is above jokes, IMO.

To me, it stops being funny when the comedian either:

• actually believes in the things they say e.g jokes about Jews are fine - if you don't actually believe they are subhuman
• keeps making the same jokes (Dave Chapelle talking about trans people every goddamn show since what feels like a decade)