They're not saying that Uber doesn't operate in a free market. They're saying that the competition between drivers within Uber for rides whose prices are fixed by Uber does not constitute a free market.
[0] - http://www.forbes.com/sites/andrewbender/2015/04/10/ubers-as...
> Uber is arguably the #1 regulatory power in the U.S. personal transportation sector.
I would reserve the phrase "regulatory power" to government. I think you're using it here for the hyperbolic value.
I am being snarky, but the libertarian poster-child is shielding 46% of the national market from competition (drivers can't compete with eachother) and that's pretty ironic.