Okay ... so which plants do not consume CO2 and convert it to O2?
Just because plants consume co2 does not mean they will all do better with more of it in the atmosphere.
http://theconversation.com/will-rising-carbon-dioxide-levels-really-boost-plant-growth-95265
https://www.theguardian.com/environment/climate-consensus-97-per-cent/2016/sep/19/new-study-undercuts-favorite-climate-myth-more-co2-is-good-for-plants
I think the point is that just allowing more and more co2 into the atmosphere will cause changes that are potentially harmful. As there are alternatives to fossil fuels it seems prudent to adopt them.

My own personal opinion is that these threads are boring. You guys had to keep doing this thing where all the people who disagree with you aren't smart enough to understand a word about the subject they're bashing.