I think you've misunderstood something. Those people are buying their own electricity...at their own expense. So, you want to bring arbitrary restrictions to electricity - as if we didn't have enough issues with net neutrality already.
>The market could solve this problem properly if there were a global carbon tax, but unfortunately, there isn't.
"Solve it"? How so? Crypto mining is largely powered by renewables (40% according to one source in Sep 2020). It is a race to find the most energy efficient way create power to make it worthwhile to mine, which has some positive effect on society by driving innovation. No idea if that is a net positive, but this is not black and white issue at all the way many here are framing it.
That’s one source and less than half does not mean “largely” in standard English usage. More importantly, almost nobody uses Bitcoin so a key question would be how that’d change if usage could be scaled up to, say, even 0.1% of daily transactions.
It's not bitcoin's fault.
So, ca. 76 of those TWh/year are still carbon heavy.