I assume he feels he's showing his players loyalty and even handedness. It might work if the players were children, but most of them are not, and they must see through this ruse pretty easily.
Regardless of where you come down in the Anderson/Quinn debate, I think few fans can look at this "decision" as a good approach. Crennel should have either given Anderson a vote of confidence, or he should have pulled the trigger on Quinn.
The head coach's primary responsibility is not to draw up playbooks, scout players, or call plays. His primary job is to decide, given the players on the roster, who will be playing on Sunday, and getting those players motivated. Crennel is failing miserably in this regard.
I predict that we will not see Quinn on Sunday, no matter how poorly the offense performs.