Because AS is on the same spectrum as, and merges with, Neurotypical. At some point on that spectrum(a small rage, actually), it is impossible to be able to say if a person has AS or is NT, because they are "borderline AS", and the diagnosis could go either way. So, since we are not real far away from NT, logical will tell you that there are more of us milder aspies, than there are lower-functioning, futher down the spectrum.The more disabled you are, the rarer you will be, because statistically you are further away from the norm(NT).
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Those who speak, don't know.
Those who know, don't speak.