I'm not really offended by it, because in a neurotypical world it IS a disability. I also have mixed feelings on it.
First of all, I agree that most of the advocates of curing autism are probably parents of children who are low on the spectrum and don't even have the ability to compensate for their autistic traits. My heart goes out to those parents and I can certainly imagine they'd like their child to be more in touch with THEIR world. Sure, we as high-functioning aspies have a difficult life sometimes, but the life of a parent of a heavily autistic child is equally difficult, if not more. I won't be judging those people.
That said, even if there's this typical shot in the arm that magically rewires your neural system and makes one NT, it's still not a miracle drug. Low functioning autists generally have a low IQ too, so taking "the cure" isn't gonna make such a child "normal"...it just changes an autistic kid with mental retardation into a NT kid with mental retardation. Sure...it might be an improvement but I think the miracle drug would be overestimated.
Then there's the fact Autistic Spectrum Disorders are PERVASIVE DEVELOPMENT disorders. A person who has been shaped by 20 years of Aspergers may no longer get overstimulated in a crowded pub and might no longer overlook facial cues after taking "the cure", but the years where they would have learned to correctly interpret said facial cues can't be won back and what's left is a neurotypical who feels like he had an unexpected sex change operation...in other words, he's confused as hell. I'm going out on a limb and say that fully grown aspies taking a miracle cure would still require years of intensive therapy before they'd be actually fully functional neurotypicals. Personally, I'd see taking a cure as a process that'd be creepy as hell; my brain has been processing information in a certain way for 28 years and then suddenly I'd have to get used to completely different messages being passed around in the ol' noggin. Yikes.
So I think a miracle cure may be nice for parents with low-functioning autistic children, just to make their kids connect to the world a little bit better, even if it's not gonna turn them into rocket scientists.
I also think a miracle cure may have a positive effect on very young high functioning autists, so they can go through a natural emotional maturing process as they grow into adulthood although this one would be mighty controversial and not necessarily ethical.
For aspy adults, a miracle cure would just mess them up completely and I wouldn't support having them take it.
The parents of the 2nd group I mentioned have a tough ethical decision to make, since the "cured" kid they'll end up with will probably be a completely different person than the kid would end up being like if he or she remained an aspy. They'd have to understand a miracle cure would leave a child quite confused even at that age already and they'd have to ask themselves if just how bad of an impact the autistic traits have...if they're enough to push a kid through such a culture shock.
I don't think a miracle cure at matured age would change one's personality, btw, even though those people would process information in a different way. A person's personality forms over time but after the adolescent's years, there's unlikely to be any major changes anymore...miracle cure or not.