Yeah. Just like what you said earlier, it really depends on each pairing developments & relationship's history.
There's actually nothing wrong with being biased, as long as it has its "ground".
No matter how much I love NaruSaku (or my other OTPs), I can still say, "This is not my OTP's moment at all" or "Well, this time is this (opposite) pairing moment. Oh well ..", if that's really the fact. Like how I love ZoRobin, although there are times when I squeal like a fangirl when I saw them together, I can still say that ZoroTashigi might have a higher chance (if there's any romance in One Piece).
Just like when Naruto said that Sakura is his gf, I don't really think of it as a moment (since it might be like his usual serious joke), but at least this confirms that Naruto still loves Sakura. Like what Inferno said, Naruto wouldn't stupidly joking like that if he really start to loves Hinata.
They said, "Minato has been dead all this time, so he didn't know that Hinata has sacrificed herself for Naruto twice! If he knew, he'd asked Naruto about Hinata instead!". Then what is their ground for saying this?
They can shout out their opinion anytime they want, but if they don't have any proof or base, then their opinion is just an opinion.