> But because he has Down syndrome, someone told him he’s different.

Yes, and him being different (in a negative way) is a statement of fact. One shouldn't be going around shouting this into the faces of people with Down's, but we as a society have to stop pretending low IQ is something to be celebrated or disregarded in people.

Low intelligence as an attribute (not the unfortunate person saddled with it) ought to be universally stigmatised and we should be doing our best to eradicate it from the population. That certainly doesn't mean we should go out of our way to disrespect or dehumanise stupid people to their faces, but there has to be some sort of policy nuance in both treating them with respect while also calling a spade a spade and acknowledging that certain traits and conditions would be better off not existing in the population.