Modeled on Gulliver’s Travels, the series was meant as an opportunity for social commentary, and it succeeded ingeniously, with episodes scripted by some of the era’s finest science fiction writers. Yet the development of Star Trek’s moral and political tone over 50 years also traces the strange decline of American liberalism since the Kennedy era.
via The Politics of Star Trek.
But by the end of Next Generation, the liberalism that once preached technological progress and human reason has reversed its priorities and now regards “progress” as incipient colonization and a threat to diversity and the environment.