It's pointing out that the left hates libertarianism and Peter Thiel, leftism is literally the opposite of libertarianism, and so you would expect a left wing news outlet to try and trash Thiel and libertarians whether or not the argument makes any sense or whether it's actually their fault. It's a bias warning.
> It's pointing out that the left hates libertarianism
It's worth pointing out that the word "libertarian" was coined for its namesake left-wing movement, what you might also call "anarcho-syndicalism", "mutualism", or similarly aligned ideologies. It's only since the 1960s that the word has been used as a synonym for ancap, and then mostly in the USA.
Corporate Libertarianism which seems to be the predominant modern one is very right wing though.