It doesn't allow for introversion, and it doesn't allow for the difference between a friend or even coworker asking "What are you reading?" and a complete stranger who means "put your book down and entertain me until the train comes." They know exactly what they're doing: if this was just about neurotypicality versus autism, answering with "just a book" or "a Pratchett novel" in a monotone and going immediately back to looking at the book would get them to go away. Some will: they might be disappointed, but they can register "he'd rather read his book than chat with me about it." Others refuse to accept that, because either they don't believe someone would be reading if they had any choice, or because they don't care: you might prefer reading to talking to them, but they'd rather talk to you than stare at the wall until the train comes.

I don't know how common that sort of self-centered/entitled attitude is among autistic people; among the neurotypical, it seems to correlate with maleness, and probably with other sorts of privilege: that is, an able-bodied man is more likely to do it than a disabled man, a rich person more likely than a poor one.