> I am not aware of any libertarian

I think you've read things a bit too hastily. I never said my example of inconsistent views came specifically or only from libertarians. (Or even the much larger group of people self-identifying that way.) The larger political group of "free-market cheerleaders" would be sufficient.

> [To #1] argument for free market isn't that all information is available.

That's not what I said. The selling-point is economic efficiency. Perfect-information is typically a required precondition within the models.

My complaint involves people who strut around boasting that they'll help usher in the conclusion while actually picking policies that sabotage the original requirement.

> [To #2] argument against cartels forming definitely isn't that secret contracts are necessary to defeat them.

"An effective-enough consideration that I can dismiss your worries about cartels as foolish" != "Absolutely necessary to end cartels"

>Perfect-information is typically a required precondition within the models.

No. That is what I was calling you out for. Perfect information is not a precondition. No libertarian I ever heard of not any economist ever argued that.

Perfect information is a requirement for a centrally planned economy. In the spontaneous order of a free economy, no one is responsible for everything – each person acts based on the part of the economy and their wants and needs that they are aware of, and people aren't stuck relying on some top-down, centralized power to impose one-size-fits-all solutions.

State central planning requires perfect information, because those in power are responsible for the entire economy. With economic freedom, each individual acts to meet their wants and needs and provide for others based on what they know, avoiding solutions based on inadequate knowledge being imposed on everyone from the top down. Because no one will ever have perfect information – people and the economy are constantly changing. The only approach that really works is freedom – letting people do as they choose with their own lives, bodies, and resources, so long as it does not involve initiating force or fraud against others.