his later ideas seemed to be worse-the whole "evolved, enlightened Humanity" thing, plus the wacky idea that Starfleet wasn't military.
My working theory is that he got confused at some point during the 'convention circuit' years in the 1970s. There's no doubt that TOS was infused with certain ideas which were revolutionary, and that Trek's view of the future has always been more optimisitic than pessimistic. But somewhere during that decade away from the franchise, where he was often asked to wax lyricial about his thoughts on humanity's future and how they related to the world of Star Trek, Roddenberry's ideals got mixed up with what TOS actually was
: an action-adventure series, Horatio Hornblower in outer space. The result of this confusion permeated the Phase II series pitch, as well as TMP; and Roddenberry returned to it for TNG. But it's not really at the core of Star Trek. It never was.
The "Starfleet is not a military" thing was always particularly :facepalm: worthy to me. You don't have an organisation on board vast ships, who talk in terms of fleets and formations and battle maneuvers; who address each other with naval terms and use naval ranks; and try and pass them off as not being a military. Undoubtedly, Starfleet is a benign
military. But their role is still broadly the same: peacekeeping, diplomacy, exploration, and yes, even occasionally engaging an enemy. Roddenberry's ideals were noble ones, but they sat uneasily within Star Trek's format IMHO.