Autistic genes, and other neurodiverse genes, do contribute to innovation, of course, and more--art, music, pattern-recognition, detail-orientedness, and possibly (if Temple Grandin is right) empathy with animals. Neurodiversity--not just autism, but all the other quirky and sometimes disabling brain conditions out there--makes us stronger, as a species, because it gives us a wider range of experience and cognition to draw on.
But I want to make something absolutely clear: The value of an autistic person has nothing to do with how skilled he is. "Existing because of natural selection" is not an indication of value; it's simply an indication of existence. What does determine our value is the fact that we are human beings--all of us, from Albert Einstein (often theorized to have been autistic) to one of my mom's most severely disabled clients, who hasn't learned speech yet and may never, but who loves his parents, speaks his mind (without words, granted), and learns and grows like any other human being.
Value has nothing to do with skill
People sometimes compliment me on being good at something, occasionally even stating, "You shouldn't let them label you. You're too good at (whatever talent they're complimenting) to be autistic." I'll leave aside the fact that intelligence and talent are a great deal more complex than that to ask: Why is it that "good at something" and "autistic" are mutually exclusive? I think it's part of the leftover prejudice from back before we knew what we know today about disability: The idea that, if you're disabled, you're not allowed to be good at anything. You're not allowed to excel, because if you do, you're subtly threatening peoples' sense of superiority. "But you shouldn't call yourself disabled! Look at what you can do!"
Nor is an autistic person who is talented in some arbitrary area in any way superior to someone who isn't talented in that area. I can communicate in writing; does that make me superior to somebody with dyslexia? Nope. I can live on my own (except for a few things I still need help with, in unusual circumstances); does that make me superior to someone who needs 24/7 care? Also no.
And it's not even like there's some kind of an orderly progression from "mild" to "severe" in autism. I mean, yeah, some of us are a great deal more disabled than others (it is a spectrum condition, after all); but when it comes to individual talents, we're all over the place. You can't predict from one skill what some other skill will be--autistics tend to have skills all over the place. I remember when I was in third grade, when my skills were probably the most scattered. I was reading at a college level, doing first-grade math, singing (and carrying a tune) as well as a teenager, and had the interpersonal skills you might expect of someone maybe eighteen months old. I know people who are labeled "very low functioning" who can do things I can't do, and it's not just savant syndrome, either. We've just got very odd brains, with very scattered skills. For autism, that's normal.
No such thing as a worthless life
I also beg to differ with something that Simon Baron-Cohen said in the interview: the idea that natural selection still doesn't offer an explanation for autism that is "completely disabling".
Two things: First, there's no such thing as "completely disabling" autism. Show me somebody who's completely disabled, and I'll show you somebody who needs to be wheeled to the morgue. Everybody contributes to the world, whether they're engineers, grocery baggers, or just members of their families and communities. People contribute just by existing.
When Joe Average sees that Jane Autistic is being included in society despite that she cannot earn enough income to provide for herself, he realizes that this society has a safety net. It leaves Joe Average free to specialize and become an expert in one thing, rather than spending all his time on making himself as self-sufficient as possible--because he knows that, were he to fall short in some skill or another, society would be willing to fill in the gap. Without altruism, a society cannot advance because everyone is looking out only for himself. If society does not value its most vulnerable members, people will spend so much of their energy on not becoming vulnerable that there is little left over for innovation.
Second: There's a pretty simple natural-selection explanation for autistic people who don't invent fire or make technological advances. When you have a genetic trait that's beneficial to a society, but which comes along with a more severe form that eliminates the benefit, you'll keep the more severe form because it uses the same genes as the milder form, and eventually enough genes will come together (Google "genetic loading" if you're interested). Sickle-cell trait, which offers protection from malaria, is an example of such a phenomenon: Two genes, untreated, and you die. One gene, and malaria can't get a good hold on you. That's why the sickle-cell gene is so common.
Leave No One Behind
Ethically, of course, it's a no-brainer: People with severe disabilities are just as valuable as people with mild ones, or people with no disability at all. Leave aside utilitarianism, and focus on the Golden Rule, and your conscience simply doesn't let you claim that one person is worth more than another. Everyone has rights--the absolute same rights as everyone else.
But sometimes, I see people who say, "I'm high-functioning. I'm not like those low-functioning people over there." And then they advocate for the rights of high-functioning people only, by whatever arbitrary standard they're using today to define "high-functioning", because at some level down deep, they're still trying to justify their existence. They feel like they've got to say, "I'm valuable because I can do X, Y, and Z", and distance themselves as much as possible from "disability". They don't realize that the solution is to challenge the disability stereotype that they're taking for granted. And they don't realize that it's valid to say, "I'm valuable," no strings attached, with disability or no disability completely irrelevant.
When I say I want autistic people to have the same rights as everyone else, I mean all autistic people. Everyone has the right to be listened to, to be respected as a person, to be free from abuse and neglect. Everyone has the right to go to school, to be hired for the jobs they can do, to be free from prejudice. Everyone has the right to be himself, and not to be forced to be someone else's idea of who he ought to be. When we advocate for autistic rights, we have to remember that. We have to advocate for the rights of ALL autistics--not just the ones that society finds interesting, intelligent, or inspiring.