This perspective I agree on. Specifically, markets are a tool for finding prices, because we've observed all throughout humanity that alternative methods of pricing (and hence resource allocation) go poorly. It's the least worst system! If you need to do that thing (establish prices and distribution of resources with minimum waste) then the market is a great tool.
If you're trying to solve some other problem (establishing "fair" pay) -- then I agree that appealing to the market is like pounding nails with a saw. It isn't even supposed to do that thing.
In Buffer's case, they're trying to go after fairness, which is fine. But this overall post above (bringing us back to topic) is that they're starting to introduce factors that are swinging them back towards the market. The market is pretty tough to ignore in the long term, irrespective of our feelings about its fairness.
But we are the ones who decide whether paying the countryside person less is "fair". The moral weight of our actions are mostly independent of what a free market gives.
The market is a tool, not the objective.