They are arguing about semantics. The labour market is a free market but not a totally efficient market as some participants use their power over demand or supply (huge corporations, unions) to drive different outcomes to a perfectly competitive market where all participants are price-takers.
> The labor market is a free market. If you don't agree the employer offer is fair, you don't have to accept.
You disagreed with him while not actually addressing his point at all. Care to elaborate how you think he's wrong here?