I didn't read it as an endorsement of theft, but defining theft as malum prohibitum, contingent on a time, place and legal system, is a flawed argument. Laws can be wrong. But the fact that a bad law or an unjust system bans theft does not make theft ok. Lots of bad laws enable theft (e.g. those enacted as post-justification for land theft), which also doesn't make it ok. No bad law can sanctify what is morally and universally wrong, and no rebellion against a bad law can sanctify it either. When we say a law is bad we mean: There is a larger moral framework in which it is unjust. Therefore the same is true in resisting bad laws: Resistance can't justify morally repugnant behavior. That was the point I was trying to make.

I didn't pick indigenous land theft to score points, but only because it's the most obvious example of some type of unregulated theft still being universally recognizable as wrong - and it's frequently brought up by many of the same people who make the case that other types of theft are in the service of justice.