It isn't the ecological damage, or the frat-bro culture, or the security issues, or the cost of Ethereum gas.
It's the entire philosophical basis of “Web 3.0” and the Capitalist urge to monetize everything from land to every momentary thought inside our skulls.
Not everything needs to be a source of income. Not everything needs to be stamped with ownership or carved up and rented out. Not everything needs to validated and valuated.
They said Capitalism would end up eating itself by running out of new markets and inventing increasing useless baubles to sell at increasingly inflated prices to an evaporating consumer class that can't even afford to feed itself.
Imagine if they had known about NFTs back then.