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.
I certainly support not using it as describing a person as “delayed,” but there are non-offensive uses such as vehicle ignition timing can be advanced or rétarded. (Accent used here only to bypass the filter)