No it doesn't, and you have to blatantly ignore the power dynamics between groups to compare the two.
Your analogy would hold only if people with mental disabilities started trying to reclaim the discriminatory connotations of the word by using it to describe themselves.
I think there's a very obvious difference between a group reclaiming a word that has been used to marginalize them and discriminate against them (N word, Queer etc.) and people who are not part of that group using the word to mock each other - and by proxy - the group of people the term is used to mock, and perpetuating its use as a derrogatory term.
Radio edits are a thing and every rapper who uses that word finds it gets censored a lot.
And context here is people picked the terms for 4chan-humour value, and it's quite hard to argue non-autists lolling about how an instance of their behaviour is a bit like an autistic stereotype, or hehe trader is an anagram of how uninformed we think these trades are is an obvious candidate for the meaning being completely unrelated to the use of autist and retard as terms of abuse. Same as if I decide to categorise my friends using derivations of a four letter word: I'm doing so because it's a four letter word, and I don't get to play the 'but I meant it affectionately, specifically and non-literally' card if someone asks me not to swear in this establishment
I certainly don't think it's necessary for Discord to ban them, but if your jargon is chosen for edginess, you don't get to act surprised if someone decides it's too edgy.
A terrorist speaking in an encoded message to cause wilful harm is still liable for it, even if the words don't exactly say that.
Language is all about context.
If we were so strict about language, most Americans wouldn't qualify to graduate 3rd grade for their botched up spelling of British English.