The in-between was disregarded over a nitpick for it not being "perfectly" carbon neutral.

That person would complain because the carbon footprint of my fart is too big.

What downside? I really do not understand what you are talking about. Your only critique is that I said "no carbon footprint" instead of "a much smaller comparatively insignificant carbon footprint", which in my opinion is just dishonest nitpicking.