The author assumes that all EVs behave like Teslas. Other car manufacturers are aiming for simpler UI, and the charging system itself is meant to deal with the oddities of deciding exactly how much to charge the car to. For instance the often don't show a charge percentage but an estimated range with bounds.

I apologize for not bringing a link but there is a beautiful story of real world range that shows that Teslas are systematically over reporting their range. It was posted recently. The author should probably read it before generalizing...