Both of this illnesses are in a way just debilitating enough for a sjw. You can have one or both of them and still reach a good position in life; also some really respected people in history were claimed to have them and were still awesome. Albert Einstein for example was quirky but is nowadays kind of a shorthand for a brilliant scientist.
AD(H)D and autism inflicted people also get positive attention from their families and other people who know this stuff and understand the limits and reasons for that behaviour. It's easy for a sjw to see that and want to have it too, kinda riding the bandwaggon.
If you are intelligent chances are that you don't get your diagnosis until later in life; something that must be like a tumblrina's wet dream. You can get a handicap everyone can pity you for but still get something out of it that makes you superior, too. And people with either or both disorder also try to look at the positive aspects of them, because if they weren't, life would be just a hellhole sometimes. But this is another thing a sjw can claim for themself to feel special about themselves.
AD(H)D at least is described with kind of a catalogue of shortcomings and the thing is that this stuff also happens to normal people from time to time. The big difference is that the one with the disorder experience that shit much, much more often, even if they actively work against it.
Other disorders are much more fucked up. For example I could only imagine a true narcicist being proud of of being one - everyone else knows that this kind of people are fucked up big time and should be avoided if you are vulnerable to them and care for your own mental health. And so on...
