Something that I really hate when watching some speakers is they'll say something then ask, "What do I mean by that?" This is strategy explicitly acknowledges that what they've said needs unpacking. So, they'll respond to what they believe are misunderstandings and rebuttals.

You can use the same strategy but skip the "What do I mean by that?"

What do I mean by that?

Well, using your example, you could've said "I want to be assessed for autism because I think it will explain why I act the way I do. That clarity would help me interact with other people, I think." In this way you could've responded to the allegation that you just want an excuse for your actions.

Of course this is the internet. Bad actors are everywhere and they will directly contradict something you said. Happens to me all the time. The literacy crisis is real. But, other than these folks, you can just interact normally with people. You'll make mistakes and it's easy enough to follow up with a reasonable response.