It is, but that's not what Thiel is trying to do. He is backing an unrelated lawsuit in an effort to squash them. The action that he had a problem with, them outing him, is in no way illegal, so he got into a proxy war against them. That is unquestionably unethical. The ethical thing for him to do would be to come at them head on in the public arena.

Especially when you champion yourself as taking the moral high ground. "The right to face your acccuser" as opposed to "having them bankroll your opponents behind the scenes".

Libertarianism: "All the parts of government that benefit rich folks are legit/necessary/essential. All the parts that benefit poor folks are illegitimate/aggression/tyranny."

That's right-wing libertarianism. Libertarianism was first formulated by a French anarcho-communist named Joseph Déjacque in the late 1800's, who lambasted Proudhon (of "property is theft" fame) for not being sufficiently focused on liberty.

Right-libertarianism on the other hand was basically an attempt at reformulating the theories of Ayn Rand and von Mises to something that would allow a common from on many issues with liberal groups on the left.

Either way, his position is not hypocritical.