Agreed, from what I've witnessed, humour is usually used in a form of empathising with peers or a form of group-initiation (new people tend to get poked fun of to see if they're good natured vis a vis a good fit in the group). I tell the joke about how I set a boiling pan of water alight (it's true, and I'm not sure how) because I'm a far better cook than most of my friends; I use the joke to actually reduce any social imbalance because I make it at my own expense. I could easily make a joke at my friend's expense, but then we likely wouldn't be friends for very long.

There is a very big difference between being fun and making fun. The OP IMO is way off, perhaps this is the social norm in Germany, but in Anglo-culture most jokes are self-deprecating. It's rare that aggressive (belittling or demeaning) jokes are made and go over well, people in senior positions using this type of humour are at risk, in fact it's one of the main reasons employers get sued because it frequently creates a hostile work environment. If you think your joke is so funny that you want to get sued over it, well I believe it's still a self-depreciating joke, because either way the joke ended up on you, but it depreciated your bank account too.

The few exceptions when aggressive jokes are allowed and found funny is usually between close friends or family and it's usually classed as a roasting joke where the entire point is that they're respected more for showing their good nature.

Comedy on TV is very different from comedy in real life. The reason why most doctors don't crack jokes is because they're insured to work, if they start insulting their subordinates with aggressive jokes, their insurance goes up and the same is with almost any antisocial behaviour, because the insurance company is thinking "How long until this idiot calls an obese patient a tub of lard and we have to fork out a hundred-thousand dollars to shut the patient up".