The tldr for this is Neurodiversity

Almost all disabilities exist only within the context of a culture. They are a human applied label.

I recon most disabled people can do more advanced complex tasks than any animal/pet. Yet we do don't think of our pets as disabled.

We are all born with a useless appendix, which can potentially burst and kill us. If someone was born without. Would we all have a disability compared to them.

Someone with only one arm is considered disabled, extra fingers? If its not the default it’s considered disabled.

Now imagine a humanoid alien race with only 1 arm and a hand with 6 fingers. And imagine what their keyboards may look like. A normal human in their society would be considered disabled. Not because you cant use the keyboard but because you would struggle using a tool not designed for you.

Now the reason why you still want a diagnosis even when you agree with the above is simple. Society has not evolved this perspective. We can accommodate almost all disabilities but they key to getting that help is by first bureaucratically “registering” yourself as disabled by a medical professional.