I think that’s because they’re actually aware of it. Most older people actually have no idea what autism is or means. So many people think autism means non functional, can’t speak, can’t do anything independently when in reality so many autistic people are literally just normal ass people in nearly every way. So if you think autism looks one way you never realize you need to make accommodations for all the people who experience autism in a different way, you never even realize they have autism and need accommodations to begin with. Unless you tell someone you’re autistic and what accommodations you need they can’t know