Neither is PoW and PoS, but it's still a question whether those differences are meaningful and worth the tradeoff. The argument is not absurd, there are real costs to the PoW approach worth considering.
The PoW powered by solar is different but it's also a mythical beast. By design there would be no way to legislate the kind of energy the mining part uses because it's opaque to the users of the network. The only thing reasonably open to legislation by a country are the interfaces of the network with the countries financial system and by then it is impossible to determine the providence of the energy it used. It's also impractical to make enough energy where coal or other fossil fuels aren't economical to mine blocks in a popular PoW scheme.