It's not! Everything you do wastes energy to some extent, the question is how much, and what you're getting out of it. The reason people are mad at crypto is that the benefits are marginal (I mean, it's some fraction of how our money changes hands. Some people have fun with it. I'm fine with being generous, but its benefits are super concentrated and I agree that it's not really very good at its mission of decentralizing currency or whatever) and the energy usage is massive. I mean, there are other things that use a lot of energy too: cars, planes, manufacturing, etc. but we do call them out for it, and when a company says they're committed to the environment and does some token "green" work we hold them to the same standard. The reason you just hear about cryptocurrency more here is that, well, this is a technical forum where it's a frequently encountered topic.