This is true. One of the reasons I haven't pursued a possible autism diagnosis is because of the amount of (often completely legal) discrimination that could be applied to me because of it. Such as I could be denied an organ transplant on the ground of a "more normal" person could have it instead. Yes, this is actually legit a thing.
On the other hand, if you do have a diagnosable disability or condition and you do seek a professional evaluation, you can gain access to a lot of community, health, and other assistance resources that you might not have been able to otherwise. It's a very personal decision, and it come with both benefits and draw backs, so you'll have to weigh your options carefully.