I don't think there's really much left to argue. Oregon threw for 178 vs Utah and 176 vs CU. Oregon knew they weren't going to be able to throw very well since neither Alie or Lockie are good passers, and that's why they only ran 21 pass plays, as opposed to 58 run plays, against the Buffs. (Against Utah they threw 30 times, ran 40.) The Ducks rolled up over 300 yards on the ground vs CU, and had 222 yards rushing against the Utes, 86 of which came in garbage time against the Utah 2s and 3s on Oregon's last drive when they scored to make it 62-20. You're right that the limited data don't prove that Utah's secondary is good, but they also do not prove that they are bad. To someone who didn't watch the games or didn't pay attention, the stats may suggest that Utah's secondary isn't very good, but as I said before, this group is better than simple statistics may suggest.

As for your point about Cal's secondary, I'm not terribly worried about it because of their defense's inability to defend the run. Utah will likely go run first and use the read option all night, and I'm guessing they'll probably finish with close to 300 yards rushing. No denying that Goff will make plays, but Utah will force Cal to be one dimensional because they're not going to give up much against the run. It's very hard for any team to win if they can't run the ball, even if they have an elite QB.