Besides the assumption about the number of holders, it's not clear how a holder contributes individually to power consumption. What if you own a wallet and don't do transactions? What if you're "hosting" it on a publicly traded company's servers?

In my understanding, there are many stakeholders when it's about bitcoin technology. Be it miners, traders, holders, exchanges... BTC is not solely a common legal entity (like: country, company) nor a widespread regular resource (as: oil, gas, water). It's more like the Internet; another protocol to exchange information(+value). Then, who is going to fairly assess the overall energy consumption of The Internet? Thus, the logic followed in that assertion is incredibly hard to understand (but unfortunately popular nowadays).