Its not just greenpeace. Basically anyone who knows how much power is wasted by mining btc would agree. This forum is a bit of an echo chamber though so doubt my option will hold much sway.
Most Bitcoiners reach a point where they begin using alternative energy to mine. I personally wouldn't have a 12kWh solar system if it weren't for Bitcoin. Now with them using Bitcoin mining to cut down on wasted natural gas, you can even make the argument that Bitcoin mining is a positive for the environment. Sure, it's still a net negative, but making progress. When you consider the industries that Bitcoin is attempting to replace, there is a chance it ends up being a net positive for the environment. We just aren't there yet because people will always chase profits over doing what's right. You can only hope at some point a majority of Bitcoiners are so rich that they prioritize the planet over their pockets.