I do think that some misdiagnosis occurs, but such a claim must be carefully qualified. Autism is not a fictional condition designed to fraudulently extract benefits from health insurers. If I had to guess, based on experience, I imagine that most cases have been correctly diagnosed.
Angle's complaint about health insurance coverage for autism appeals to a segment of the population that finds other-izing too appealing to resist. Their problems are always due to someone else who is cheating, never mind the taxpayer benefits they receive but rationalize as fair. The childless pay for schools for people who opt to have children, with no limit on how many children they can educate at the expense of others (8 kids in public schools, maybe 40-70 grand a year on someone else's tab); the younger generation pays for Medicare for the older generation, regardless of how personally responsible some people might be for their health problems; some people serve in the military for many others who don't bother.
The list is long and I am not objecting to any of these benefits or complaining about the unfairness of these benefits. I'm just noting the selective attention to "unfairness" in the system and the tendency to find fairness in benefits when one is on the receiving end. Everyone invents a notion of "deserving" that allows them to check the deserving box.