I don't recall the argument, and whatever it was I don't think it has anything to do with my current position (which in any case is not AnCap). I can, however, give my nutshell argument against AnCap, since you're seeking alternative views.

Againt rights-based AnCap, a la Murray Rothbard: how are the first property right actually established? The Lockean metaphor is flowery and beautiful, but still just a metaphor. Ultimately, the theory has no normative teeth and has to take its most important premise as an axiom. Also, consequences matter.

Against pragmatic AnCap, a la David Friedman: My prior is fairly heavily against AnCap being the most efficient (or even more efficient, or even possible) and while Friedman does provide evidence to move the posterior in favor of his hypothesis, it doesn't do enough to change my mind. Not that I don't think experiments such as seasteading shouldn't be tried, mind you - the information is certainly valuable. There's just very little direct evidence to update the prior at this point.