Keep in mind that the industrial processes that consume fossil fuel also contribute to quality of life in various ways. Improvements in emergency response and early detection infrastructure alone have resulted in deaths from extreme weather events reaching record low levels. Poverty as a whole has seen record-breaking decreases over the last 30 years.
So there are other factors to weigh besides how much contributes to CO2 emissions.
If you have a certain argument to a certain talking point, then you're always going to repeat that same argument whenever that talking point emerges. There's nothing bad faith about that. These kinds of arguments get repetitive so you're going to see people repeat the same points.
As for the value of debate, even bad debate is better than nothing. Sometimes it feels like there's nothing being gained from it, but if you question people who have engaged in a lot of debates, you find that they're much more informed after the debates — even very acrimonious debates, where both sides are just trying to defeat the other side — than they were before it. A society needs people to communicate, for it to progress in its ability to effectively coordinate on complex social issues, and that process of communication is not going to be without warts, given how complex these social issues are, and how high the stakes are for a great number of people.
Societies which embrace civil discourse and protect free speech are far better off for it. This killing strikes at the heart of a civil society.