Median employee tenure is almost entirely dominated by things other than employees leaving. A company that is not hiring will not have any new employees and as a result have a really high median tenure.
The question you really want to ask is: what's the percentage of people leaving each year?
They definitely try their best to give every candidate as fair a shot as possible, but there's always going to be error. It becomes a question of what type of error hurts more, accidentally rejecting someone who's qualified or accepting someone who isn't. They reasonably believe the latter is significantly more dangerous.
You know exactly what he meant. You are using the word design in a different way than him.
There's absolutely a part of the brain that specializes processing visual information, just as there are organs throughout the rest of your body that specialize with other different tasks.
The question you really want to ask is: what's the percentage of people leaving each year?