We all use syllogism, and so do the rankers and odds setters, it's necessary, but not sufficient. Upsets happen (duh). They mean something, close wins mean something too.
UGA nearly lost to Auburn, it was 50-50 or so for a while. That would have dropped them from 1st to maybe 12th or so. Same team, ball tipped a different way, major shift in perceptions.
This also highlights a problem with a soft schedule, had UGA lost, they don't have much left to regain #1 status. If they won out and made the playoffs, fine, but they'd likely not be a one seed (to the extent that matters).