Sure, and everyone's a little diabetic, too, because we might have low blood sugar at times.
The phrase is illogical. Everyone has characteristics that are comparable to autism, sure, but that correlation is not the same thing as being autistic. Autism is not just a collection of random traits. It has a specific cause, and I doubt that NT traits that just happen to coincide with its symptoms have anything to do with that cause in its extremity.
I've also seen the phrase used with poor intent more often than it's used as a tool to promote empathy. From what I've seen, it's most commonly applied thus: "Well, we're all a little autistic, so buck up and deal with it." My oldest sister came home from grad school with this phrase in her pocket, and my mom summarily tossed out any concerns she'd previously had over my traits. Because if everyone's autistic, my autistic traits aren't autistic, they're normal. It's a twisted rationale, but I think that's where the phrase came from: If everyone's autistic, no one's autistic, and we don't have to acknowledge it.
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I have not the kind affections of a pigeon. - Ralph Waldo Emerson