I guess I am expecting too much out of educated people.
As the OP has said, it's really a matter of understanding what size the chickens will be when grown, most people making this error are newbies.
And how much more space is needed for the birds to move around and flap their wings.
Hatcheries list chicken sizes by the pound, not dimensions.
The unique nature of the chicken hobby leads to many people getting started while never having the chance to meet an adult bird (biosecurity).
What they are doing is causing a great deal of new chicken people, who think they are giving birds a great life, to actually be inhumane... while spending more than they have to.
But it's so much harder to admit a mistake when it's been going on for a while.
That means birds have to suffer these torturous coops long after the owners start to doubt the situation.