The lyrics of the song in its opening credits made secular humanists (who are the majority of the trek fan base) cringe.   The theme alone was an affront to one of Gene Roddenberry's core principles about star trek.

Instead of orchestral themes, it had this cheap wannabe pop song.

Instead of moral dilemmas, it had tits.

Instead of shakespearean stage actors and drama professors playing well-balanced and noble characters, it had typical TV actors playing trigger-happy rednecks.