It's extra special too, because you can arguably say that 'retardation' isn't a legitimate medical disorder anymore. At least when I worked with special needs kids, those that would have previously been called "retards" before were classed as "intellectual disability" or "general learning disability," although I saw and heard those terms a lot less often then I did the terms for what was specifically wrong with them.

Basically, the only valid use of the term 'retard' anymore is a verb (or other parts of speech) that mean "the act or result of delaying or preventing." As in, a sentence like "reducing spending in a developing country retards economic growth."

But that's not so with autistic. It's not only "in style," it's a legitimate mental condition. That's the official name.

So what seems to be "in style" now is what is going to be the most offensive because it has strong contemporary connotations to conditions and people.

Really makes you question how benign those words are when they're only popular if they paint as large as swath of the population as bad or undesirable as possible.