with a very poorly performing QB with no signs of improvement from last year against a decent opponent? (never mind our remaining opponents are projected to be much better) I doubt you're saying that "we don't know if GB will be better so better not try him out," bc that's dumb.
Starters are benched all the time for little or no experience backups. In this case both QBs have D1 experience, and GBs results are better. Even Hillstead has experience and better results (not that much better but factor in Retzlaff's fumbles and I would say he is that much better)
Lastly, hearing the main reasons Retzlaff won the job, doesn't translate into games - 1. he doesn't turn the ball over and he 2. "unlocks the offense" Well, he still turns the ball over like crazy and the offense looks almost completely locked up (out of 14 possessions - 7 three and outs and 2 four and outs). He's probably a good practice QB and not a gamer, he's not the first. And unlike last year, he doesn't have the excuse of the Oline being poor - since they look much better.