Because it's not a free market with those with deep pockets manipulate the rules that get enshrined into law.

Which means there can never be a free market since there will always be people able to bribe and manipulate in order to get their way. It doesn't matter how much oversight and transparency you have, those things can be slowly chipped away overtime and replaced with laws that favor the ultra rich at the expense of everyone else. I'd love to be wrong about that, but I've never seen an example of a country where wealth had no power to influence law.

That's not capitalism or a free market, it's corrupt governance and was never an intended 'feature'

Because capitalism is an entirely different concept. Capitalism is an economic system of relations that prioritizes the right to exercise one's existing capital to accumulate more of it, hence the word capitalism. So-called "free markets" is a utopian concept that is not a requirement of capitalism and of course has never existed in any honest sense of the idea.

Free markets arguably exist in the plant and animal kingdoms.

Sure, I can accept that because it is a concept fundamentally at odds with civilization.