Well, like everyone else in the western world, they probably assumed Shanny wanted a say in GM decision-making, either directly or through his hand-picked GM. So, why would Ralph and Russ pick a GM BEFORE talking with Shanny. Given the title he just took with the Redskins, a sort of co-GM with Allen, Ralph and Russ would have been correct in this thinking.
Now, the interesting thing is the timing of the Cowher visit and the promotion of Nix. It can be assumed that Cowher may also have wanted final say in GM type decisions. Given that within days after visiting with Cowher, Nix gets promoted, and Cowher has yet to come out and distance himself from the Bills job, the natural deduction is that the Nix promotion may have been floated to Cowher who did not reject the idea. Hmmmm.