Free market means it's free from control and corruption, and the price is determined by voluntary trading, and not manipulated by central banks or etc.
I hope you guys are not so naive to confuse "free" as in free from corruption, with the other meaning of "free" which is with 0 cost.
That is the problem: libertarians are all for free markets, but have a totally wrong idea of what "free market" means.
It is NOT a market free from control or regulations.
There are several requirement for a market to be a "free market". Among them: there must be several suppliers, and consumers must be free to choose among them, or do without the service. Consumers know the price charged by each supplier in advance, and, if they pay that price, they will get what they paid for. Most importantly, suppliers can increase their production if they find it is in their interest, and there cannot be
unfair barriers preventing new suppliers to come into the market,
if they have the required capital and expertise.
A market can have a ton of regulations and paperwork and licenses and bizarre licensing and auditing requirements; but it can still be a free markets, as long as those conditions apply to all suppliers, and there are entrepreneurs who could meet them -- if they saw a profit in doing so.
The theory then says that free markets are good fro mankind, because, in a free market, the suppliers will enter or leave, and adjust their prices, until the price will be just high enough to cover the cost of efficient production plus a return on investment as good as any other activity -- that is, maybe 10 percent per year.
The "fee market" would fail to meet all of these conditions. To begin with, there is only one supplier -- the bitcoin network -- and all bitcoin holders are forced to use it. The supplier would not be allowed to increase the supply, because the block size would be limited by the developers' decision. The clients will not know the fee that is required to get confirmed in N minutes before they send their transaction. (They will only know it after N minutes have passed, by inspecting the blocks that have been mined.) No matter how much they pay, they cannot be certain to receive the timely service that they thought they were paying for.
Indeed, what the "fee market" advocates want is the exact opposite of a fRee market: they want to create a monopoly market, where the single supplier limits the supply to a level that will guarantee him maximum return on investment. Which means much reduceed benefits to society and a much higher price than what a free market would provide.
The only free market that could exist in cryptocurrency would be the market for e-payments among competing cryptocoins. But that does not seem to be free in the US either...