Most of classical Star Trek (TOS, TNG, Voyager, and large parts of DS9) consists mostly of self-contained morality plays where the sci-fi just provides a setting. Some of those morality plays are related to the science part - notably a lot of the issues around the morality of treatment of Data and holograms. But most of it could be set in any time period. The Sci-Fi setting just made it easier to juxtapose things without running into "but that's not how it was then/there" objections and allowing more extreme contrasts.
Enterprise, parts of DS9, Discovery and the new movies have largely done away with that format. It's a very sharp relief.
Enterprise, parts of DS9, Discovery and the new movies have largely done away with that format. It's a very sharp relief.