They don't just warm up there Macs when it's time for their first ranking and make their "OH MY" face at who they 'find out' is good while evaluating all information available to that point equally.
They are human and humans do human things, like being influenced by things they already know about such as the AP and Coaches poll.
No one will ever convince me they aren't biased by the rankings already in place when they start theirs.