But a libertopia/ancapistan wouldn't do $THING_THAT_THE_EMPIRE_DOES?

That’s because it’s not one.

If you want one of those, a society that pursues only the end of maximum choice for everyone, the Rim Free Zone is ↑ that way (rimwards).

Be careful though, because various factions, regions, cultures, and subcultures within the Rim Free Zone have very different choices to make, which is why you can find bits of the RFZ as Utopian as the North American Confederacy (of L. Neil Smith’s The Probability Broach, et. seq.) and as distinctly not-Utopian as Jackson’s Whole (of Lois Bujold’s Vorkosigan Saga), with New Hong Kong (the Foglios’ Buck Godot: Zap Gun For Hire comics) somewhere in the middle.

Plus the odd world where everyone is so psychotically devoted to not exploiting anyone that they have ended up living naked in the woods and eating grass. So it goes.

As many a philosopher there has said, consensualist ethics is the beginning of wisdom, not the end. It successfully teaches you “don’t be evil”. How to “be good” on the other hand, is where we get into the Nine Excellences and the Five Noble Precepts and the Code of Alphas and approximately 8,000 years of people trying to figure out how to bring about the perfect marriage of the perspectives of truth and beauty in an unflawed universe, the March of the Flame Against the Fall of Night; i.e., actualizing the Good, immanentizing the eschaton, all of that.

In short, there are lots of values and virtues which embody moral truths over and above that basic ethical core. If you didn’t notice that, I suggest a discarding of preconceptions and a deeper re-reading is in order.