So if there are children having terrible things happening to them, feasibly some of those children then go out to a shop and on top of the terrible things happening to them they are made to feel crap by some adult making a joke at their expense.
You can't tell by looking who is having an awful time.
People don't have labels on them so you can easily see which person you are about to push over the edge.
So if your 'joke' is not that important why is your whim to 'have a laugh' more important than somebody else's feelings when you have no idea what harm you may do?
Is being careful about hurting someone else's feelings so difficult that it will destroy your life NOT to make that weak joke?
And if you are a person who 'doesn't intend any harm' by your little joke - why would you get defensive and argumentative about being told by someone that those little jokes are not harmless?
Surely a reasonable person would be glad to be given the information that allows them to avoid hurting someone's feelings?
And if another person's feelings are completely unimportant to you then why are you making a joke with them? If you don't care whether you hurt them why would you care if you amuse them?
Or is it all about you?
Why is it so often that the person hurt is told to 'suck it up' and get tougher but the person doing the hurting doesn't get told to change their ways and learn not to be upsetting to others?
As for somebody being neurodivergent and that being the reason for them making the unfunny joke - it is perfectly fine to tell someone who isn't NT that their joke is not funny and that if repeated to other people may well upset them and please can they not do that any more.
If someone punched you in the face thinking it might be funny because they didn't understand it would hurt - the excuse they didn't intend it to hurt would not hold water.
You would tell them it hurt and explain why they shouldn't do it again.
I don't see why emotional hurt is treated differently.