If an autistic person overexplains something to you they probably don't think you're dumb they just think THEY would appreciate those details if they were the ones being explained to
A lot of things that seem obviously implicit in speech AREN'T obvious to autistic people. So we inherently think it's necessary to specify things that might seem transparent to neurotypical people because usually WE'RE the ones who need those explanations
plus, autistic people grow up knowing significantly less than neurotypical people about things that neurotypical people consider very important, but significantly more than neurotypical people about things that individual autistic person considers important.
so like. autistic people are used to being told ‘why don’t you know that? everyone knows that!’ about stuff they didn’t know until right then... and also being told, ‘how should i have known that? how do YOU know that? why did you even learn it?’ about stuff they’ve known for years.
with the constant back and forth of ‘everyone knows that! you must be stupid’ and ‘how did you ever learn that? you must be smart’, a person starts to really appreciate a nice thorough explanation.
