I am guessing you never use public rest rooms? Many stall doors have a vertical gap by the lock for extra clearance since they are designed to be cheap. Especially public school bathrooms.
I have been in quite a few countries, everyone poorer than the US , yet somehow , as cheap as they made their bathrooms, it isn't possible to look into peoples stalls.
The only place I've seen adult toilets like this is in a prison tour.