I found the Language Log article rather wryly illuminating, particularly in that apparently, across the pond in England, "a BBC survey ranked 'spastic' as the second-most offensive term for disabled people, just below 'retard.'"
Now wait just a goddam minute here. Who took over a perfectly legitimate, precise piece of medical terminology and stripped away its medical meaning such that it became a pejorative "slightly less offensive than 'twat' and 'piss off,' and slightly more offensive than 'slag' and 'shit'"?! Granted, that's in British English, where, if they aren't creatively mangling the language out of some kind of perversely offhanded dismissive contempt for loanwords, then every second noun, verb, and adjective has some kind of pejorative connotation. However, the rest of the Language Log post suggests that "spastic" isn't doing so well here in North America, either.
The passage that particularly sticks with me from the comments to the article (and if I could find where to send an e-mail to the poster, I'd comment too, in a similar vein) is this one:
When it crossed people's minds that I actually was a spastic, they were usually surprised and bit embarrassed by having said something with a sense that they hadn't thought of. Then, depending on testosterone levels, whether they liked me, and how polite they were, they either apologised or didn't. But I knew that they knew that they felt they should have. So it must have been reasonably offensive...
I have a similar anecdote, since, if it isn't entirely clear from context, I do have Cerebral Palsy, and I actually am a spastic (quadriplegic). A colleague of mine at my last full-time gig liked to sneak up to my office door in the mornings and rap on the little glass window, which, of course, would startle me, and I'd jump. She started calling me "Spazz," which I put up with for a while, since I just sort of assumed she knew that was kind of accurate for me. Then one day, I said, "You realise that I actually am a spazz, right?" The dialogue went as follows:
Colleague: Get out!
?!: No, really, I actually am a spastic quadriplegic.
C: You're kidding me!!
?!: No, c'mere, I'll show you...
...whereupon I went to Google and searched for "spastic quadriplegia" -- just to prove my point.
She turned approximately purple and spent about five minutes falling all over herself to apologise for having ever called me "Spazz" in the first place. Now, that's kind of too bad, since as far as I'm concerned, "Spazz" is one of the if not nicer, then at least more accurate nicknames I've ever had. It certainly didn't bother me too much. On the other hand, that does beg the question: How the hell did "spastic" become so much of a pejorative that some people aren't even aware that it's a legitimate medical term?! How did that happen?
More importantly, how can we stop it? I'd really like my descriptor back from the forces of bigotry and semantic pollution, thank you.