That would punish Washington for making the championship game and having their only loss be to a playoff team they beat earlier.
Just making the conference championship game doesn't carry much weight given how conferences have difference formats. The having beaten them factor may carry some weight, but not enough given it was a 3 point win at home earlier in the year in a game they were outplayed
Ohio State and Michigan basically played the Big Ten Championship game in Ann Arbor this past Saturday. The game in Indy is a result of poor conference structure -- having divisions.
The committee thinks highly of Ohio State as well. They were #1 for two weeks, while Washington was #5 for three weeks.
They'd be punishing Washington for barely scraping by for most of the season. Style points matter in college football. The eye test also without question matters