I don’t think he’s that far off.
From my read of this, the software had the effect of producing better MPG at the cost of higher emissions.
Heck of a tradeoff there. Burn more gas/pollute less, or burn less gas/pollute more.
Ironically, the one with worse emissions may actually do the environment less harm; the acid test would be the quantity of pollutants emitted per mile driven.
If your vehicle produces ten percent less emissions but gets twelve percent less fuel economy, you're actually emitting more pollutants per mile.