I think both of these forms of political activity succumb to one basic critique:
People are in denial of this obvious fact:
Being part of a civilization requires you to cooperate with others, usually through some central authority or power.
I guess where I agree with libertarians and anarchists is that less government is more effective. Economically, I’m a libertarian; keep stuff simple, avoid the kinds of weird economics that require tons of regulation. Letting the markets handle things is usually far more efficient than government; that doesn’t mean the government should just cheer while rampant commerce destroys culture, people and environment alike.
I can understand libertarianism as a statement against bureaucracy. Who doesn’t find that appealing? But as a political idea in and of itself — that’s as ridiculous as unfettered socialism!