It amazes me that we are still talking about Malthus. There has been a Malthus in every generation since the one to actually carry the name, and they've ways had "compelling" arguments...
...and always, life has gotten better and resource starvation has always gotten rarer...
I used to think its roots lay in some kind of biblical fetish for armageddon. I have no qualifications in this area though so this is just my armchair-psychologist theory.
Oh that and often weird racism about how many people live in poor countries.
It can't just be those two things, though, because it's really big in the U.S. right now on the political left, and especially that part of the far-left that relentlessly mock the right for both their religion and their supposed racism/"whiteness".
In some ways, it's an anti-economic-growth, anti-capitalist sentiment that portrays the great conflict of the world as between "the world" and "human economic activity"
But there's a lot to unpack in the question "Why won't Malthus die" that I won't claim to understand at all.
I suspect other parts of it has to do with tribalistic mentalities and the Morton's fork.
If others have things you want then they are stealing from you. If others are poor then they are a threat because they might want to take what you have.
Belief in the neccessity of one's actions is one hell of a drug that sticks a magnet onto their moral compass ensuring it always points to "correct".
The whole debate is predicated on the belief that we are running out of earth's capacity to accommodate our waste CO2, so it doesn't make any sense to mockingly cry "Malthusian" at the suggestion that further capacity issues lie beyond.
It might be running out of capacity to do so without changing in ways we care about. Possibly.
But I do note that there is a distinct lack of interest in any attempts to solve that problem other than shrinking the population or dismantling our economies or ending any semblance of liberty.
Indeed, most of the proposals are so extreme and draconian that they would lead to much more misery and death than simply doing nothing.
Nobody is interested in even considering alternatives. Research to solve the problem is ongoing, but barely funded at all -- and yet tons of things are possible.
Sure, fusion is interesting.
But, other things are too. Safe and plentiful fission power would help, and is available today.
Work on the chemistry of photosynthesis is promising -- imagine a truly carbon-neutral hydrocarbon fuel (the carbon in the fuel having come out of the air through artificial "plants"), but is barely funded at all.
Direct carbon sequestration is an expensive, but possible, option (probably cheaper than just rolling society back to the middle ages!)
But 99.9% of the energy is instead spent on terrible fantasies like "fundamentally restructuring" the economy away from profit and liberty.
Because there is no desire to actually work the problem. Just like the original Malthus didn't care about the plight of the "surplus population," but instead had a political axe to grind.
...and always, life has gotten better and resource starvation has always gotten rarer...
and still, Malthus won't die.