TCU only lost one game, to Baylor, which created the tie at the top of the Big XII where Baylor was the conference champion, not TCU.
Was TCU a great team that year? Yes. However, should a team that did not win it's conference regular season or title game (the Big XII didn't have one) be a national champion? If you are Notre Dame or BYU, or other historical independents? Then yes. But TCU was in the Big XII and didn't win the Big XII that year.
The Playoff teams that year
OSU - lost early to a bad VaTech team (I could see TCU being ahead of them) but then they had wins against MSU (8) and Wisconsin (18) on their way to winning their division and conference. Right or wrong, a 1 loss team that didn't win their conference versus a 1 loss team that did, is not a travesty, especially with a win against a team that finished in the top 10 of the CFP final rankings.
FSU - undefeated heading into the playoffs, and were destroyed by Oregon
Oregon - lost one game to a very good Arizona team, which they avenged in the Pac12 title game (beating Arizona 51-13, they are sort of like this year's OU). Again, only had 1 loss, were able to avenge it and win their conference title.
Bama - lost to the previously mentioned Ole Miss (who was destroyed by TCU in the Peach Bowl). Went on to win the SEC with wins over Miss St (7), Missouri (16) and Auburn (19) along the way (those are the final playoff rankings after the championships).
TCU
1) Didn't win their conference
2) Played two games against teams that finished in the final CFB rankings and went 1-1
3) What would be the justification for putting TCU ahead of Baylor? The Bowl results?
I like TCU, and have attended many TCU football games. But that loss to Baylor killed them because it basically made sure they couldn't win their conference unless Baylor lost again, and they didn't. By the end, they were a great team, but I have no problem saying they didn't deserve a shot at the title, because they didn't win the Big XII.
The Va Tech loss was too bad to overcome. And Baylor played an absolute dog shit OOC schedule and got smoked by West Virginia.
But it is not an injustice that a one-loss team (in which it gave up 61 points) that also played a weak OOC schedule that mopped up a crappy conference did not have a shot a title. I will lose no sleep over that. They weren't deserving of a shot at a title, even if they were more deserving than OSU.
Obviously the No. 4 team is often capable of winning a title when it gets hot at the end of the year. But rarely is even that fourth team deserving of a claim to the title. None of Baylor, TCU, or OSU were. I won't lose sleep over their lack of inclusion.
In point of fact, Baylor and TCU were co-champions, and there were no tie-breaker provisions. So, the Big 12 submitted them as co-champions, and that's how the committee evaluated them.
I also don't give a shit whether or not the conference annointed you their champion. A conference championship is an insular, partial view of the season that should be irrelevant to determining who should be or compete for a national championship.