Capitalism and the Free Market are NOT the same thing.
Capitalism is an economic system that works best when there is a free market. That doesn’t not automatically mean that capitalism IS a free market.
A free market requires an even playing field. Capitalism leans towards to concentrate capital and creating monopolies, creating an uneven playing field. I think most agree that monopolies are bad for the free market. Yet monopolies are not a bug of the free market, they are a bug of unchecked capitalism.
Article from r/Libertarian: For a Free Society