Not use terminology that I think has bad connotations.
I have, and it hasn't changed my opinion. I don't think his description of this consistent cycle is accurate: I've never heard anyone use any of the currently-used technical terms as a synonym for "stupid." The cycle pretty much ended with the word retarded. I think y'all are simply choosing to ignore how it's actually used. It's used to say "you being stupid is you being like this other person with a mental condition." Since this kind of logic is generally communative, I don't think it's unreasonable for it to be seen as implying that someone with one of these conditions is insult-worthy per se. You can say an association shouldn't exist, but that's academic: the point is that it does. That's how language works. A good example of this is the word "niggardly." It has nothing to do with the racial slur, has a totally different etymology (it comes via Scandinavian languages versus the slur being based on Romance ones), but given its effect, it's something that most people avoid using now. See also: "nimrod," which literally went from meaning "a great hunter" to "stupid" thanks to a massive misunderstanding of a Bugs Bunny cartoon. Regardless of the reasoning, there's a degree of selfishness involved. You're basically saying "I won't change my speech pattern even though it's hurtful to someone else." Sure, anything can be taken too far, and some of this is simply a matter of general societal agreement that is not perfect. But are you really saying that you're so inconvenienced by having to use a different word, to the point that it overrides the very real hurt felt by someone with such a condition or their loved ones? Even if we set aside the way it's used (and what thus makes it different), is it really so important to you that you're cool with being an asshole to someone who doesn't deserve it just so you get to use this one specific word? This is why the "anti-PC" crowd gets a bad rap, because my experience has overwhelmingly been that it's people being upset that they're not allowed to be shitty to someone else like they used to.
That was a more general thing about the whole idea of being "anti-PC" or whatever. So my comment to you more specifically was to question why it's okay to use a term that many would regard as offensive for little gain, at least that I can see.
I've heard special needs used as an insult. I haven't heard anyone go to Stanhope's lengths. I've not really followed this whole conversation but check this out: https://www.themarysue.com/sarah-palin-son-instagram/ That lady is a piece of work.
I've been having that internal debate a lot lately. I feel like it probably starts as cynicism and then just sort of becomes the person after awhile.