Exactly! That is what they should be arguing, that the amou to of co2 in the atmosphere is so small that it can’t possibly be making any impact whatsoever. What does have a slight impact in select areas though is places with large tarred areas, but the amount of impact globally is negligible as Forrester areas and larks etc far outweigh the parking lots worldwide
We need dissolved CO2 in the blood to be involved in the chemical reactions which convert highly toxic blood ammonia into much less toxic and excretable urea. Called the urea cycle among other names. Check it out in a basic biochem textbook or online.
I always bring out that fact if some CO2 paranoid bloviator talks about how toxic CO2 is. As mentioned earlier CO2 is plant food. And plants make oxygen...so CO2 is a very necessary commodity.