It is another of those "feel good" rules that seem to have the opposite of its intended effect. Some teams already have coaches in mind, but are forced to interview minority candidates if their desired coach is white. Unfortunately, since the rule was put in place, minority candidates have been subjected to token interviews. To me, this is worse than not getting the interview in the first place. You are telling the candidate, "we really do not want you as the coach, but we are being forced to bring you in to make things look better."
I think that the NFL needs to rethink this rule and provide a better solution. To me, this rule is absolutely insulting to minority coaches.