Dungeon ecology and world ecology are different.
Living dungeon ecology rarely makes sense in old-school modules - Caves of Chaos especially springs to mind immediately, as does the rise of the funhouse dungeon (which lampshade the ecological mistakes by turning the whole thing into an artificially-constructed gauntlet). The whole "what are these fifty orcs living in the dungeon for months even doing for food?" or "how can a carrion crawler just have a nest right next to the gnolls without conflict?" type scenarios are definitely hallmarks of old school adventures. I think that's what rredmond was talking about.
Funny enough, I personally believe that modern authors' attempts to swing this the other way tend to be the biggest culprit of that ultimate Brycian sin of describing what things used to be - the author wants to make dungeon ecology too plausible, to the point of getting into extraneous details that don't matter in play.
I do not worship at the altar of Gygax. However, in terms of defining "old-school play" I think his words are relevant. Review the section "Monster Population and Placement" in the DMG at p. 90 to see what I mean.
B2 didn't make sense in terms of scale generally (look at the scale of the overland map). Leaving aside the obvious errors, I think this was in part because of the limitations of non-digital technology ie. having to fit the caves of chaos into a single two-page spread on paper. And it as a training module, so the kind of hex map seen in the D series wasn't appropriate. And it was Basic, which Gygax was trying to convince people was a "kiddie" system, so he probably wasn't worried about it. Compare that to T1 or S3 or S4 or Isle of the Ape (Dungeonland and its sequel obviously don't count).
There is a vast divide between the Gygaxian idea of putting stuff where it makes sense to be, and writing an irrelevant backstory for every room. I suspect the latter started when DMs/writers were trying to justify why they were putting things where it
didn't make sense for them to be (usually a futile attempt since only the DM knows the backstory and it still seems arbitrary to the players, if they care). It got picked up by adventure writers who wished they were novelists (reading Dungeon Magazine is like watching American Idol auditions, if the judges didn't cut them off and automatically let them go on to the next round). And it was allowed so much it became the standard.