The first time I ever heard that term was in an old issue of Flex when some guy calling himself "big Frank" wrote a letter to Ronnie Coleman's monthly column. He talked about his diet, and training, and said he was sporting the "full house" look. Well, as nicely as he could, Ronnie explained that he was most likely deluding himself with how big he really was, and that not only could is pose health concerns, but it didn't really look better for anyone concerned with their appearance (from an aesthetic point of view obviously). Coleman added that if he was honest with himself and cleaned things up a bit, sure he may not be as "big" Frank, but he'd look, and feel a hell of a lot better. Certainly more like a bodybuilder, even if an offseason one.
Now, with that said: I understand competitive powerlifters, or strongmen (I'm friends with quite a few), who don't worry about bodyfat, because they're performance athletes. Sure, they have their low moments where they admit that they wouldn't mind being a bit leaner, but if the added bulk helps them in their chosen pursuit, then so be it.
In my opinion, the reason people argue this back and forth, is because it's falling under the guise of bodybuilding. In bodybuilding, mass plays a huge role, but so do proportion, and conditioning. As such, die hard BBing fans (competitors, followers, wannabes) will be quick to jump on anyone using the "full house" excuse for inflating their gains.
For someone with no intention of trimming down that's perfectly acceptable, but whether it's bodybuilding or not,... that's what people will constantly bicker about.
(and another can of worms opens...)