Ok, so Dr. Who fans...
Also, you have to remember, they weren't actually "primitive". They were just hippies. They understood technology, and had even lived in the city, but chose to leave it's sterile walls to live closer to nature, away from a life they considered boring and meaningless.
Edit: It's on DVD now, plus they have optional added CGI if you like that sort of thing. The villains have gone from transparent tin foil to humanoid energy beings.
I like watching it with the original effects though.
I've recently watched Invasion of Time, and they specifically do refer to themselves as Time Lords who dropped out of the academy. Likewise, the Doctor refers to Drax as a Time Lord even though he never graduated from the Academy either.