What year were you born? Are you a convert?
There absolutely was a teaching that there were less valiant in the pre-existence. Oh, I know, history is being re-written constantly in the LDS world, but I know what was taught and what wasn't.
Of course there were different levels of "valiance", faith, commitment, and focus on individual progression and development in the preexistence. But "fence sitting" implies neutrality, not varying degrees of obedience and commitment. That idea is Mormon folk doctrine, and nothing more.
Oh, and if you're going to try to argue the "official doctrine" line, I'll remind you there is absolutely no official doctrine in the church, never has been.
I now revise my original observation. You're knowledge of LDS doctrine is not marginal, it is sub-marginal, about where Scratch resides on the continuum of knowledge of Church teachings.
Either that, or you're just another in a long line of tendentious provocateurs that congregate in forums such as this.
Official doctrine is easily discerned, and true doctrine, even if not official, can be discerned from other kinds of teachings in several ways, one of which is decisive.
You and harmony really should take this whole dog and pony show over to RFM where the roads are paved with tin foil.