You know the drill — waste of energy etc etc nothing new.
I believe all this can be summarized as "let's make people use some altcoin we can control, such a Solana which uses pos"
Conveniently, the "green" alternative to pow is something nations can control much easier, pos.
It is easier just to buy coins or coerce the biggest holders (I.e validators) then having to buy hardwares, expend a he'll lot of electricity, etc.