Elon buys bitcoin, tesla buys bitcoin, tesla accepts bitcoin, then announces he is selling bitcoin simply because of the energy usage and tesla will no longer accept bitcoin for purchasing a tesla.
Do you really think Elon didn't know about the energy problem? Do you really think Elon putting people on Mars is environmentally friendly?
He is simply manipulating the crypto market for his and only his benefit in mind.
I agree that it is hard to believe that he didn't know about the energy problem. Tesla's market cap is down something like $200 billion since they announced buying bitcoin, but maybe Musk is playing some reverse psychology game-
https://mattelston.com/2021/02/10/elon-musk-a-reverse-psychology-genius/