I think that may be about the character's perspective (since Rudy at his most moral is literally just grillman ), but the treatment of slavery as just something in the background that everyone just tacitly accepts is one of the major failings of the later books, even if slave traders are consistently portrayed negatively and have an antagonistic-but-too-concerned-with-self-preservation-to-actually-be-antagonists role. In contrast, one of the earlier arcs has the moral compass character massacre slavers wholesale and this is uncritically presented as a good and correct thing to do. That's one of the few areas where the series got worse as it went on instead of better.

Actually I think most of the problems of the later books relate to that refusal to actually grapple with the evils of slavery, with how Julie is at once effectively an adopted daughter to both Zenoba and Rudy whose technical education would make her one of the foremost experts in several fields and at the same time is still explicitly and literally their chattel property (and they don't even seem to understand the concept of emancipation and adoption/business partnership as a means of further entrenching power over someone particularly talented and valuable, which was a cornerstone of the classical slavery systems its heavily drawing on), or Linia technically being an indentured servant even as she's the warlord boss of an international PMC/intelligence agency alongside Aisha (who invented the concept from first principles). Rudy repeatedly internally calling out and being annoyed by Lilia grooming and verbally abusing Aisha but then never actually doing anything about it until she just kind of stops doing that on her own is another related issue of just tacitly accepting shitty things going on around him. It's kind of funny that the implicit sexism of the world and the attitude people had towards his daughters is about the only thing that actually made him give any pushback on the world's shittiness at all, given he started out as a raving misogynistic dipshit even worse than the world he was dropped into.

But yeah, I don't think there's anything in the books that made me think the author was anything but a kind of vapid lib who's maybe good on some things but awful on others, even when the books were being very good in general like with the treatment of the horrors of war or how the ultimate conflict is completely pointless and wasteful and doesn't end in glorious victory but is instead just over and everyone is diminished by it, or even more subtle things like how despite being mostly a first-person story with a power-fantasy harem protagonist all the female characters are capable and have their own independent stories and goals going on in the background even when the narrator-protagonist isn't looking and Rudy's impulses to be patriarchal and sideline them are actively reckoned with and treated as wrong.