If stupid ass Auburn had beaten USC in the opener they'd be out of the picture. If stupid ass Auburn had beaten Ole Priss we'd already be SEC West champs. Then the Iron bowl comes and we need Auburn to lose and hurt USC's SOS...and stupid ass Auburn wins.
It would have hurt USC more because their common opponents would have been 0-1 in that game, whereas ours would have been 1-1. Since we played both teams, we wanted Bama to win.
For LSU it doesn't matter because we played both. USC, on the other hand played Auburn, so if Auburn got beat by Bama it would help LSU's SOS relative to USCs.