1000s of data points are evidence, even if they aren’t logged in a lab notebook. No one except ideologues needs a study to say men are stronger than women; the broad outline of the autistic manner of speaking is equally obvious. The details are worth study, but you have to have no exposure to the relevant populations to argue with the existence of the difference.
Oh, you mean like, I dunno, actually measuring them!?
You seem to have misheard "this is excessive extrapolation and theorized details from too little hard data" as "the most-general version of the phenomenon doesn't exist."
> 1000s of data points are evidence
Except they're the same kind my neighbor uses when he says that kids these days are different and don't respect their elders like they used-to.
There are several places where the author has created mockups of how they think some data would look if it were collected.