Ugh, this is new (around here): I just reported and blocked a trollbot who was literally posting the "CO2 is plant food" nonsense. For a moment, Mastodon smelled almost like Twitter, and I'm hardly nostalgic for that unbearable stench.
Anyway. No, fuckwits, plants have absolutely no need of your CO2! Plants had existed long before mammals appeared, not to mention humans. The only thing the excess CO2 you produce does is causing ever more climate destruction.