It has been a while since the onset of this rather unfortunate pattern, but the use of "唐" and its derivative "🍬" to address whatever day-to-day behavior that they seem to be used to refer to, is quite infuriating.
Down's Syndrome is a genetic disorder. Patients nearly always have some type of disability. Mockery and discrimination towards people with Down's Syndrome is therefore a type of ableism.
Please stop clowning around with exlamations that create random and unsupported references to Down's Syndrome, or, in fact, any other condition that may correlate to disabilities. This behavior is disgusting, profoundly disrespectful, uneducated, rude, impudent, etc. It demonstrates a toxic and arrogant lack of empathy towards people with Down's Syndrome.
But what about freedom of speech?
Interesting point, but mind the difference between what is legal and what is right. By the text of the statutes this may be legal, but note the historical background of the 1st amendment—note that most clauses relating to freedom of speech intended to disallow limitations on political speech as to prevent a tyranny of government. I don't see how shouting "Down's Syndrome" at everything fits into any valid political purpose.