Was thinking the same thing... There's no evidence I can see to suggest the parent is not also against other forms of excessive energy consumption.
Personally speaking I find it just as irritating of a pattern here that knee-jerk calls for "regulation" (i.e. bring in the coercive power of the state) or outright banning are so often floated as a/the solution to every problem. When legal coercion is suggested, it is entirely proper to bring up the existence of the dragons that lay down that road.
If cryptocurrencies didn't have the energy footprint, I would find them pretty uninteresting and/or ridiculous for various reasons, but ultimately it wouldn't bother me that people do what they do with them. When they start adding seriously to the global energy load in a time of climate crisis that makes them pretty offensive.