Are you sure "every single car on the market that wasn't redesigned for 2017 got its ratings "downgraded" twice"? I can simply name 2016、2017 FWD CX-9's which don't get affected and there're more!
Like I said, some cars didn't cross a whole MPG threshold when they were downgraded.
One car might have gone from 29.4 to 28.5 (0.9MPG drop) without the rounded rating changing while another from 29.5 to 28.4 (1.1MPG drop) with the rating dropping by 2MPG.
I was merely reflecting many new 2nd-gen CX-9 owner's opinions on gas mileage. YMMV.
Every car equipped with an MPG gauge has many owners dissatisfied with gas mileage.
Among the most dissatisfied will be people who had a car with a speedometer that under-reported speed that now have a car that shows the actual speed (Mazda).