Not wanting to be the arbiter of political correctness on WP (but heck I have just awarded myself that title)
Laughing at ones own habits/behavior/impulses/compulsions is ok. Where I am from we call that self-deprecation which the English are famous for in comedy.
Laughing at jokes that make fun of other people's habits/behaviour/impulses/compulsions is ok if the group that are being made fun off are at top strata of our social hierarchy. Again in our traditions we are allowed to poke fun at the ruling class whether they be wealthy, celebrities, politicians or royalty etc etc...
However, laughing at jokes that make fun of (the above) is not ok if the group that are being made fun off are vulnerable members of society. For example laughing at an autistic person who has a compulsion to lick windows is not funny. It is cruel to both the person (particularly if it's a child) who perhaps can't help themselves and it's cruel to the parents and family of that person.
On a seperate note: the particular moment I lost respect for Donald Trump was when he ridiculed the disabled. For somebody who is the most powerful man on earth to think that disability is funny tells me he is not our friend.