Categories only make sense if they are useful, and if you make them so imprecise that they include everyone then they are useless.
By expanding the criteria for the autism spectrum to include everyone that displays even a single trait associated with autism we would be doing a disservice to the people that display a larger amount of those traits (i.e. the ones that are on the spectrum with the current consensus), since they would be invisible in the midst of everyone else.
OTOH “spectrum” is such a vague term that you could claim everyone is somewhere on it, even if it’s almost always the bottom end.
Categories only make sense if they are useful, and if you make them so imprecise that they include everyone then they are useless.
By expanding the criteria for the autism spectrum to include everyone that displays even a single trait associated with autism we would be doing a disservice to the people that display a larger amount of those traits (i.e. the ones that are on the spectrum with the current consensus), since they would be invisible in the midst of everyone else.