Or it's simply financial motivation. Any steps taken will cost them money, and the problem is likely not going to really become a problem until after they are dead and gone. They'll be spending the money, but will personally get no ROI from it. Therefore, they choose to do nothing.
That's probably true of many, and it couples well with motivated-disbelief. Confidence that if it happens it won't really be a problem for you makes it easier to just shrug the whole thing off and refuse to think too much about whether your disbelief makes sense.
It's worth mentioning that there's one more position that actually does make sense, even if it's a bit Pollyanna-ish: The belief that science will find a less impactful way to address the problem in the future. The argument is that we shouldn't trouble ourselves now, we should just wait for the new tech that will fix it.
I actually subscribe to a weak form of this view. I think we should be acting now to address climate change, but that we shouldn't do anything too drastic, because technology is going to improve and find better solutions. The world is actually making significant strides toward emissions reduction, mostly in the form of low-emissions electricity production, and not because of a moral obligation but because renewables are cheap! That's the sort of thing that generates real progress, without much pain.
I suspect that atmospheric carbon recapture will always be extremely energy-intensive, but we are on a path to extreme but intermittent energy abundance, and carbon recapture sounds like a great way to spend the extra terawatts when they're available. I think one of the things we're not doing enough of now is research into carbon recapture and sequestration. Reducing emissions can never get us to net-negative CO2, and we need that if we want to actually fix this problem in anything less than a millennium, so cutting emissions is insufficient. The corollary to that is that cutting emissions will likely become unnecessary before we get very close to zero.
So, the conclusion of the weak-form of this techno-optimisim is that we should be working to curb emissions, and we should be directing tax dollars to recapture and sequestration research (and geoengineering, too), but we shouldn't go so far that we reduce economic output.
What I'd really like to see us do is to take a very market-driven approach, facilitated by carbon taxes. Pick a reasonable per-ton price and apply it at the point of extraction, where it's easy to identify and track, so that every downstream use has the carbon tax built in. Fossil fuel consumption that doesn't burn it and release the CO2 can apply for a rebate to recover the carbon taxes on the carbon they didn't emit. Couple that with carbon tariffs which attempt to impute to foreign-made goods the CO2 emitted in their production. Anyone who can prove they're capturing and permanently sequestering tons of carbon should be able to capture that as a refundable tax credit. Planting trees should count, as long as there's a plan to keep that carbon sequestered for several hundred years -- and if the trees burn, the tax liability comes back. Oh, and a small percentage of the tax revenue should be earmarked for climate mitigation research. The rest can just go into the general fund, ideally displacing other taxes, and maybe funding progressive offsets since a carbon tax would be mildly regressive.
There'd be a fair amount of bureaucracy in defining and administering such a tax, especially the tariff part. But it's manageable, I think, in particular because it doesn't have to be perfect, it only has to be good enough that everyone is incentivized to avoid 1-2% of their emissions this year, another 1-2% next year, and so on, and good enough that there's actual money to be made in recapture and sequestration for anyone who can figure it out. With that, we can sit back and let the market solve the sort of problem it's good at solving. We might need to tune the carbon tax rates a bit from time to time, and we'll want to scrutinize the system regularly to identify loopholes to close, but mostly we could just consider it a solution in progress.