It’s not worse. It’s carbon neutral

So replacing their gas with carbon neutral gas will improve the situation by 100%.

Referring to things as carbon neutral is typically shorthand for net neutral CO₂e (or net-zero) CO₂e.

You're pedantically right that the machine is not creating or destroying carbon atoms, but the things it does create have massive "carbon dioxide equivalence". Or, phrased differently: the emissions of this equipment are equivalent to emitting significant amounts of carbon dioxide.

They also reek havoc on people's lungs.

This is worse than air, but better than doing nothing I suppose. The situation is not "improved by 100%". It's marginally better, but definitely not 100%.