"If there's nothing inherently bad about energy consumption" is assuming a lot. In theory we could produce all the energy we need with wind, tides, solar, hydro, fusion, zero-point energy, or whatever. Then there would be no issue. But we don't live in that world. We live in a world where most energy in some places is produced with enormous externalities. In other places, the externalities are fewer, but wasting this energy generating bitcoins doesn't eliminate the other uses of the energy, so the aluminum smelters or whatever that might have used the clean energy buy their energy from a different source that pollutes. And if most of the bitcoin mining is happening in China, most of it is being powered with the dirtiest energy source: coal.
You assume that a substantial portion of bitcoins are being mined in populated areas where the energy would otherwise be used for what you deem "better" purposes. How do you reach this conclusion?
The article does not make any effort to investigate the location of bitcoin mining facilities or sources of energy being used. For all we know, 99% of bitcoins may be mined using sustainable energy, off the grid. Without this information, any estimation of raw energy consumption is meaningless.
