A permaban? No, I don't believe that saying "You're an autist" or the sort should lead to that kind of punishment, unless it gets out of hand.
Honestly, I tend to be one of the guys who uses those kinds of sayings quite frequently without being toxic, if that makes any sense. Like, I'll casually say something like that to a friend when he gives up first blood or doesn't rush IE on Syndra (I usually go for "retard" or "fegt"). I wouldn't want to be banned because of it, because I'm saying so in jest to a friend and there's no harmful intention in it. So who is being hurt by that? Honestly, words shouldn't warrant ban if they're not used to specifically target someone, I believe. To get banned for "Hate Speech", it should not be because I said a specific word towards someone, but because I expressed the belief that someone is lesser or worse of a person because of a specific trait.
I think an example would be...
If you fed in a game and one of your teammates simply says something like: "You're an autist" Leaves, that wouldn't really be something I consider permabanworthy, but rather something you would report them under the "Unsportsmanlike Conduct/Verbal Abuse" maybe. Because they're just using the word and not really hating on you for the fact that you are autistic (and how would anyone actually know if you're autistic/gay/female/male/white/black/asian/etc?).
However, if someone heard or thought you were autistic and immediately started going after you for that, then sure, by all means, report them for "Hate Speech" and someone like that deserves a lengthy ban, if not a permanent one.
Yet, using a word as a general insult could never really be considered deserving of a complete and utter permaban just for using a word. I think it's how you use words that should dictate a punishment that severe. Then again, I'm pretty impossible to offend, so I might just be completely desensitized from that kind of stuff. I'm thrown quite a bit of those "adopted" jokes and they're true -- but that's it. I don't see it as a bad thing, but I can definitely see and agree why people would consider it bad. Meh.