Which human right would that be? The right not to be made fun of?

The right to dignity, presumably?

Unless what he said resulted in direct abuses of the person from other people, I can't think of what he could say about a person that could possibly constitute a human rights violation.

Singling out the child wasn't in the child's best interests. There's article 16, which is the right to privacy; article 19 which is about protection from harm.

Perhaps someone can find the court documents so we can see which human right they say was being violated.

It wasn't just some random child -- it was a public figure. Where do we draw the line?

Yes, that's the point, he rather brutally insulted one specific disabled kid. I find it to be different from just telling a joke about a politician, for example. Can you publicly insult someone, by using a form of joke? I don't know, either. But the title sounds as if he just "told a joke" - that's misleading.

Remember Susan Boyle from a few years ago? The talent show star with the great voice who perhaps wasn't the most attractive woman in the world? Hundreds (probably thousands) of comedians have jokes commenting on her perceived ugliness. Was that hate speech? Should they all be punished for it?