Science fiction writer Charles Stross ruined his Merchant Princes series for me with its explicit anti-Bush politics, but I agree with him about Star Trek. I liked it when it was new in the 60s, even retained some interest in it in the 80s. Now I see it’s as bad as the old Edgar Rice Burroughs’ tales of Mars.
That’s because, as CS says, ST merely pastes the sci and tech on top of its storyline, whereas good scifi builds the storyline out of plausible sci and tech which informs the story’s world. Now if he’d just forgone using his fiction for his personal political propaganda, I’d still be looking forward to his books.