The fact that it was used in a sci-fi programme has nothing to do with whether that meaning is correct.
The writers of the sci-fi show may have picked up on the false "little dark one" etymology and used it because they thought that's what it meant. That doesn't mean they were right; script-writers aren't name experts and there's no reason why they would know what constituted etymological accuracy and what was simply a misunderstood etymology, or even made up nonsense.