Without the community of grifters, neither BTC or ETH would have any serious market value, and so they would be extremely easy to attack. The only reason vast mining networks can exist is because of the huge amounts of money that grifters have been pumping into the system. The "community" probably understands this very well.
> Sidenote: I would hazard a guess that the people memeing about "oh my energy use" haven't looked into it with all that much detail. Fiat is MUCH worse in this position.
No, fiat is processing literally millions of times the amount of transactions of BTC & ETH combined for a fraction of the energy use. Sure, the whole financial sector is larger in energy use than BTC and ETH, but most of that is all the parts that BTC and ETH don't cover at all - insurance, loans, risk eval, customer support, investments, KYC and AML, and many other functions that are crucial to the economy.