Yes, I understand what you mean. It's like how a diagnosis of dyslexia would prove that a person wasn't merely lazy for being bad at reading and writing.

But even if you don't get the diagnosis, you can still say, "This is how I naturally am." And it's possible for a person to have autistic traits but not quite meet the criteria for a diagnosis. You might be just the neurotypical side of the line. And at the end of the day, it's a judgement call on the part of the person assessing you. I'm only just over the line, and the diagnosis was given to me as a "best fit" out of the available options because he could see that a diagnosis would help me. But if I'd been assessed by someody else, they might have judged things differently and I might not have got the diagnosis. But I would have still been the same, with the same differences/difficulties.

I can definitely understand not wanting to go bowling. I hate noisy social events like that. But that can also be true of a neurotypical introvert. And some people with ASD like busy social situations.

For example, in my improv group, there is another guy with Asperger's syndrome, but he is very different to me. He seems to be fine with noisy social situations, and will often hang out in the noisy bar afterwards, whereas I go home straight after our improv session finishes. But he has far more difficulty than me with social cues and knowing the right way to respond to people.

Your job supervisor sounds like an extravert who didn't understand introverts. To force an introvert to take part in a busy social event, and make that an important part of your performance evaluation, shows that he had a total lack of understanding of individual differences. Even without an ASD diagnosis, you could have whipped out a leaflet on personality types. Legally, it wouldn't carry the same weight, but it's still valid. He was in desperate need of diversity training.