It would be more accurate to say that most of Star Trek depicts life in Starfleet, a pseudo-military institution (Roddenberry insisted that it isn't, while war

It would be more accurate to say that most of Star Trek depicts life in Starfleet, a pseudo-military institution (Roddenberry insisted that it isn't, while war isn't Starfleet's main purpose it shares enough traits with modern armed services to suffice for this discussion). There is always a lesser expectation of privacy for military personnel, even in the US armed services. While there are elements of communism depicted in the Federation as a whole, those are facets of a global post-scarcity society that has somehow evolved beyond the less "progressive" bits of human behavior. I'd argue that the biggest fantasy of Star Trek isn't warp drive, but the notion that humans are somehow less violent than Klingons.