In a pure voluntaryist market system everyone gets 100% of the vote (i.e. veto power) when it comes to how they use their own labor and resources. If one has acquired more wealth then one has more options available and more decisions to make, but still doesn't get any direct say in how other people use their property, no matter how rich or poor they may be. This is far more egalitarian and in keeping with the ideals espoused by most democracies than the idea that every person's freedoms and property are subject to a glorified opinion poll.
Yeah, so uh... not democracy.
I'm not going to relitigate the entirety of Anarchy, State & Utopia in the HN comments section, but suffice to say that these ideals are far from objectively "egalitarian" and the idea that other's negative, non-inferential side-constraints must be sometimes violated in the context of social cooperation is actually foundational to republican (as in the political philosophy) thought.
It's interesting to see this sort of rhetoric re-emerge after it took a long break after the '08 recession. Of course, the idea that the market is "too democratic" is absurd. At least, I haven't seen a democratic system where 1% of the population gets 40% of the vote.
As long as "willingness to pay" is the market proxy for the utility a consumer gets from a good, the market is not "democratic".