Slovis played the #3 (in the Final College Football rankings) on the road while the best Retzlaff did was #15 at home. That is a HUGE difference. Next best opponent for Retzlaff was #16 on the road compared to #23 on the road for Slovis.
So again where are these best 4 teams in the conference? Did you just make that up? Well it is obvious that you did.
Now we have to go to Sagarin as the college football rankings only show the top 25 (Kansas was actually rated higher than OK St in Sagarin).
Guess who the next best team was? Texas Tech at #30. Didn't we beat Texas Tech? Who was the QB?
So the best win we had all year was with Slovis against #30. What was the best win we had with Retzlaff? Oh yeah, he didn't win any games.
In 8 games with Slovis as QB we committed 10 turnovers. In 4 games with Retzlaff we committed 9.
According to PFF the offensive line play in the last 4 games was far superior to the first 8 games. The main reason? No more Caleb Etienne (or at least far less).
So despite having better run blocking and playing an easier top 3 opponents than Slovis, Retzlaff committed far more turnovers and had a far lower passer rating. So what again is your question? Oh yeah, you wanted to know why Retzlaff doesn't get the benefit of the doubt for playing the hardest 4 opponents of the year. Problem is no one can answer that question because it is quite frankly a huge lie.