I've become fairly patient with climate deniers over the years since it is both a difficult to imagine idea and contains serious amounts of existential dread, making it very hard to reason about. Because of the latter I don't know anyone, climate scientists and myself included, that aren't in some way climate change deniers.
The only possible pathway to dramatically reduced carbon intensity in our economy is the potential of physical resource limitations, not intentional human action. If you study the way energy impacts our civilization (highly recommend Smil's "Energy and Civilization"), it's fairly obvious, if not hard to swallow, that we cannot reduce carbon emissions radically enough in a short enough time span without also destroying the global economy. Destroying the economy today to mitigate the worse case scenarios is risk that even right now no sane person earnestly wants to take.
That destruction, on the timeline somewhere in the next 100 years, is inevitable anyway, but nobody really wants to suffer now when the more extreme suffering we're putting off might be in 20 or even 60 years.
This is really the heart of the problem: the immediate cost of addressing climate change has always seemed too high given the perceived uncertainty of outcomes. In 1950 it would have been fantastically easier to put a cap on carbon emissions than today, but the real threat of climate change was more than a lifetime away, and seemed ludicrous to even most educated people.
But today, meeting the emissions goals required would make the pandemic seem like black Friday as far as economic activity goes. And at the same time, while we know the impact of climate change will be bad, we still don't really know how much we'll each live through and how bad it will be immediately. Maybe we'll see the AMOC shutdown in our lifetimes and Europe will suffer massive crop failure and starvation... and maybe it will just get unlivably hot at the equator, and people from the American Southwest will have to move to the Northeast.
As many have pointed out, the pandemic is basically a toy problem version of climate change. In order to really prevent the pandemic we would have had to globally shut down the economy for a few months, much like China did. The problem is if we did that and prevented the pandemic, our world today would remain an imagined counterfactual that would not be perceived as worth the harm by the majority. We completely failed to address pandemic, and we will completely fail to address climate change. We'll find out what that means.