Taxation is theft, my friend, and in economics, all value is subjective. Thus, by your definitions above--unless I am misunderstand something--everything is "fiat," as every single money, currency, or commodity ever known to man was first and foremost valued subjectively. Even gold.

Steemit definitely has its weak spots, but ultimately, it is a stake-weighted voting platform. In other words, it is built on inequality, in a sense. The difference between Steemit and a modern day nation state, however, is that participation in Steemit is 100% voluntary and consensual. No force is being employed here to coerce individuals to participate.

It's 100% morally legitimate, in that sense.