Mainstream economists aren't central planners. I don't mean just economists from both administrations. I meant mainstream economists from every school on the US News and beyond.
But Krugman isn't complaining about Bitcoin's monetary policy here; he's complaining about the operation of the network itself. It's a pretty weak argument; he's claiming that the network costs too much without doing any kind of serious cost-benefit analysis, just an inapt comparison to gold coins.