I fail to see the logics to it. There are plenty of other modes of production than state-capitalism. And don't forget that these "unlawful" houses have several planets with resources at their disposal - the original sleeper ships were built in the middle of a large-scale space war using resources from 8/9 planets, so I fail to see why 1 nation cannot upkeep a cap fleet using resources gathered from 1-4 planets. Also you can't really reduce the Corsairs or the OC to "pirate faction" without neglecting a large chunk of lore.
To me it seems more like "I don't like faction X, I don't think they should have nice things".