There's absolutely an argument there. Easiest one being 12-1 vs. 11-1. Think of it in terms of the BCS Rankings. Georgia and Michigan are well ahead of the field, think we can all agree on that. TCU being 12-0 could be nipping at their heels as they have the better SOS and SOR compared to Georgia and Michigan. So would a loss drop their number below Ohio State who isn't playing?
Now with there being a committee and the human element, the natural thought is to drop a team after losing. The question is how many spots do they drop? If it's one spot from #3 to #4, the natural process would be to move #4 to #3, but #4 also lost. So does #5 move up even though they didn't play? They could drop TCU to #4, but leave OSU at #5 and since there isn't a team to move up into #3 with USC losing, then they both just slide up one spot to #3 and #4 respectively.
Now they don't have to, I just think there's precedent that they haven't matched up conference teams in the Semifinals yet and frankly if you're an OSU/B1G fan, why would want them to? They've allowed, on two separate occasions the SEC to match up in the Title Game, but now they're going to deny the B1G that chance? That would be a bad look IMO.