Galaxy Quest is not a Trek movie. TMP and TSFS are good movies, even if they don't appeal to everyone. This nonsense started with TFF and Generations.
No, it was definitely pre-"Generations." Hell, even before TUC came out, fans were talking, mostly jokingly, about the odd-even thing. Fans would joke that we knew TUC was going to be good when it came out because it was an even numbered film. It probably did become a thing after TFF, but long before "Generations."