I take a very firm line on insults. I think that insults are a form of social punishment, and therefore you should only insult people if the trait is (a) actually harmful and (b) something that might change in response to punishment.
So, for instance, I basically don’t think there’s a good reason to non-jokingly call someone ugly. There is nothing wrong with having a face that doesn’t fit someone else’s standards of aesthetics– prettiness is not a rent you pay for occupying a space marked ‘human’– and most ugly people can’t do a hell of a lot about their appearance anyway. Don’t call people “obsessive”, because obsessiveness shouldn’t be punished; obsessive people are the reason you don’t have to light a candle when it gets dark out. And don’t mock people for having cancer, because while having cancer is bad, mockery will not make people have less cancer.
I’m not a big fan of the concept of “ableist language”. In my experience, what happens is that if you tell people “don’t say ‘stupid’, say ‘foolish'”, they will switch from calling people “stupid” if they can’t do math to calling people “foolish” if they can’t do math, and at no point will it occur to them that maybe having dyscalculia can’t be fixed by insulting people. The problem here is not ableist language. The problem here is ableist beliefs and values.
And it’s absurd to put “moron” in the same category as “retard.” “Moron” has a history of being used as a psychiatric diagnosis, but is not currently associated with intellectual disability. The Google Image Search for “moron” mostly gives you pseudo-clever insults and a man with a lot of tattoos, while the Google Image Search for “retard” gives you this charming picture:
Nevertheless: I don’t think you should use mental health diagnoses as insults. The worst case, of course, is when you genuinely mean to imply that the person has a mental health diagnosis. As a general rule, when someone has a diagnosable mental illness, it is a sign that we as a society have said “this person’s problems cannot be fixed by the ordinary process of social rewards and punishments”. Therefore, it is basically always insulting people when insulting people won’t do any good, which is wrong.
However, most attempts to use diagnoses as insults aren’t meaning to imply people have diagnoses at all; they’re just playing off inaccurate and harmful stereotypes.
Let’s consider the joke “The Republican Party is very diverse this year– there’s two Hispanics, a black man, a woman, and an intellectually disabled man.” Clearly the author does not intend to actually suggest Trump has an intellectual disability; if they did, it wouldn’t be funny. The joke is a humorous exaggeration; but what is it a humorous exaggeration of?
Is the author suggesting that Trump has subclinical versions of traits intellectually disabled people also have? Are they implying that Trump is sometimes nonverbal, or has difficulties with self-care activities, or performs poorly on Raven’s Progressive Matrices, or has difficulty understanding articles unless they’re written in plain language? No. None of these are stereotypes associated with Trump, and his IQ is no doubt (like all presidential candidates) above average.
No, what they mean to suggest is that Trump is ignorant, that he is irrational, that he ignores evidence that’s right in front of his nose, and that he is often wrong. None of these things are necessarily true of intellectually disabled people. There are plenty of intellectually disabled people who cultivate their intellectual capabilities as best they can and who are informed about some topics while readily admitting when they don’t know enough to have a real opinion. Personally, I think it’s a tremendous dick move to insult intellectually disabled people by comparing their rationality to that of Trump.
Moving from the realm of humor: consider the phrase “psychotic killer”. Obviously, if one means to suggest that the killer actually had symptoms of psychosis, that is one thing. But a lot of people describe, say, Ted Bundy as a psychotic killer, even though he isn’t actually psychotic.
When these people use the word “psychotic”, they don’t mean to say that the person experiences delusions and hallucinations; they mean to say that the person is a Monster. Equating psychosis and being a Monster is tremendously harmful to psychotic people. While schizophrenics are at somewhat elevated risk of committing violence, so are other groups, such as young poor men, and yet no one has banned young poor men from purchasing guns or advocated for their preemptive long-term imprisonment. A substantial amount of the stigma against psychosis is exactly the fear that psychotic people will hurt you– a fear that, for the vast majority of psychotic people, isn’t true. And this is a particularly awful stereotype to perpetuate when you are referring to the actions of people WHO DON’T EVEN HAVE ANY PSYCHOTIC SYMPTOMS AND ARE THEREFORE CLEARLY AN EXAMPLE OF NON-PSYCHOTIC PEOPLE BEING VIOLENT.
In conclusion: it is okay to insult people. Do not insult people about harmless traits or traits that aren’t responsive to social punishment or in ways that perpetuate inaccurate stereotypes. Thank you.