I hear that this has been tried before but it didn’t really land because finding viable substitutes for particular terms can be difficult. I’m fascinated by language though and I wanted to take a shot at this myself.
Just a disclaimer that I’m not trying to drag anyone over using any of these terms and I’m not going to pretend that I’m some paragon of anti-ableism myself - I have work to do on this front, you probably do too and if we all work together we can make some positive change and establish better habits and a more supportive culture in our communities.
Here’s a list of words that are more socially acceptable in their ableism and some suggestions for alternatives:
Crazy, Stupid, Dumb, Moronic, Idiotic
[In the sense that something is incorrect or bad]
Silly, foolish, absurd, ridiculous, laughable, nonsense/nonsensical, illogical, incomprehensible, inscrutable, irrational, contradictory, hypocritical, self-defeating, naive, ill-conceived, inane, asinine, counterproductive, unbelievable,
Crazy, Mad
[In the sense of letting loose or being enthusiastic]
Going wild, getting stuck into something, in a frenzy, on a rampage, being engrossed, head over heels, obsessed.
Psychotic, Psychopath, Psycho
[In the sense that something is cruel]
Vicious, bloodthirsty, monstrous, horrific, sadistic, heartless, brutal, ruthless, horrendous, reprehensible, despicable, depraved.
Crippled
Hamstrung, moribund, incapacitated, impaired, ineffective/ineffectual, hog-tied (lol).
What are some other ableist words that are pretty commonplace even amongst the left that you’ve heard?
Are there terms that I have overlooked or any ones that you use yourself that you’d like to replace?

As much as you may hate debate tactics, maybe searching for new versions of “scruffy looking nerf herder” that have punch but simultaneously don’t offend anybody is less fruitful work than developing attacks on the bogus ideas being presented by your shitheaded adversaries.
This is intended to get people to consider the implicit ableism in the way they use language and to suggest alternatives so that radical spaces can be more inclusive and less oppressive towards people with disability.
I disagree with this framing.
I’m not trying to convince anyone that the necessary work is to find inoffensive ways to insult people.
I feel like this is veering into rehashing the same discussions that have taken place in defense of things like sexism, racism, queerphobia (especially transphobia) in radical spaces; no, eliminating transphobia isn’t going to be enough usher in the revolution but at the same time this is not a valid reason for ignoring or even perpetuating transphobia.