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.
Well then I think we’re pretty far off topic from what the OP was talking about. Lots of people use the r word, and other similar words, as general insults or derogatory words. And that’s not OK, since it implies that it’s bad to have a condition you couldn’t control and didn’t choose.
As for clinical settings, I’m sure they have their own rules about how to talk both to and about people. I can’t speak to that, as I’m not in any of those settings.
And when in my personal life I refer to people with mental disabilities, I’m sure there are both kinder and more specific ways to describe someone’s situation.