Would such a strategy be illegal?
Smartest guy on the planet, claiming to be saving it from climate change didn't know Bitcoin damages the environment?
If he didn't already know that, then can he be trusted? If he did know that, can he be trusted?
Also probably a good idea to check the real CO2 numbers, they often get extrapolated I think.
Sort of. The miner pools have a lot invested in special-purpose hardware. It's not clear what would happen if people tried to make a change miners weren't interested in. Yes, you can threaten a hard fork, but angry miners could freeze transactions, revealing how not-so-decentralized it really is, destroying confidence in it as a currency.
In crypto: nope.