Most say that but it is not a problem with bitcoin but there is a problem with the power source we used to mine bitcoin because most miners use home electricity mainly because it is the most convenient method they can find but this is a era where even cars and houses use solar electricity to run instead damaging the environment but yet even for a great innovative currency like bitcoin we haven't found an innovative way to mine it and we accuse bitcoin that it is making environmental damage but we already have the technology to stop that right now