If you buy into his "libertarianism == no dependence on social organization" and "space colonization == absolute dependence on social organization" than he's right. The latter statement seems likely to be true, but I don't think the former is. Libertarians aren't anarchists, and the beginnings of commercial space exploration that we're seeing today suggests that libertarian-friendly support for space colonies may be possible.
It does seem like a false dichotomy. Sure, it's just fiction, but doesn't Heinlein's "The Moon is a Harsh Mistress" illustrate how fiercely independent space colonists could work together to survive and even thrive?
