It's absolutely a spectrum, just like the individual conditions that make it up are spectra. (Everything is spectra. Is my friend who has arthritis in his otherwise working legs "physically disabled"? It depends on whether he's walking around a store or trying to run a marathon.)
"Neurotypical" here, when used as a binary adjective, means something like "close enough to the average on all the relevant spectra to not particularly benefit from special consideration". The exact line for where that is is going to be blurry and situationally dependent, because it's a shorthand for an approximation.
"Neurotypical" here, when used as a binary adjective, means something like "close enough to the average on all the relevant spectra to not particularly benefit from special consideration". The exact line for where that is is going to be blurry and situationally dependent, because it's a shorthand for an approximation.