Exactly! To you its crystal clear, but if the other party were additionally considering all the non-highway accidents, then the distinction may not be so clear to them until you provided the additional metadata.
Now consider how you may feel about a car which has decided based on all available data that this strip of road is a lane. Its crystal clear to that car until its suddenly not.
You reacted with what appeared to me to be very restrained aggression (typical and acceptable, no offense intended) as you struggled to figure out if they were just being dense on purpose or were actually ignorant. I dont feel either were accurate but your message conveyed that was what you felt to me.
A car simply says “hey i dont know what im doing anymore. Help!”
Now imagine trying to teach a car these things!