While I agree that it's frustrating to have to examine everything in the context of Demo, that sort of thing is really kind of inevitable as discussion of any game gets to a high level of competition. We're talking here specifically in the context of preparing fleets for Regionals+ level competition, which is bringing most of the best players in the world out together.
Certainly, there is a place for playing fleets because they're fun to play or based on a canon-historical battle; there's a place for non-standard fleet construction rules, asymmetric games, scenarios, juggling Star Destroyers, or whatever. But in the context of most of these discussions, how competitive the fleet is takes a pretty substantial priority, particularly for players who think they might actually have a chance of doing well in these competitions.
So, I certainly feel the same way about Demo. Just, don't misinterpret this (at least my) ad nauseam nitpicking to mean you shouldn't ever play anything that's not tuned to a razor's edge. Play stuff because it's fun, it's a game after all. Most of my lists that I consider competitive, have started by just playing something that sounded like fun.