There’s a clear campaign against the mentally ill with the global rise of fascism. Lots of it shows up in anti homeless rhetoric, but you can see it in the MAHA and anti vaccination movements.
There’s no reason to use the word “r-tarded” to describe someone. As someone who’s worked with the intellectually challenged, it’s an insult to them to compare them with people who are willfully ignorant.
The support for that is weak: the influence is mild & easily overcome. An insult isn’t meant to be productive, it’s supposed to convey contempt & unflattering ideas about the recipient of the insult.