If I am a State fan, I think that my coordinator is great and your coordinator is a risk. Likewise, as an SEC fan I think that coordinators hired by SEC schools are better hires than coordinators hired by ACC schools. As a Southerner, I am likely to believe that ACC, SEC, and Big12 Coordinator hires are better than Pac10, Big10, or Big East hires. (For those interested, see research done by Simpson and Brown, Johari, and several others from 1985 to about 1995)
The second layer is external validation of expectation. That is, because we primarily characterize the quality of event through subjective lenses, we seek to validate our qualitative judgments via the input of others. For instance, when I sip a nice zinfandel and I am alone I am likely to be very satisfied. If, however, I am with someone else and they make a face or say, "Boy this sucks," then I will begin to re-evaluate my initial assessment. The tendency for human beings is to stick with their initial cognition and we will attempt to explore the external input for inconsistencies. (What sucks? The wine itself or the glass it is in? Do you normally drink zinfandel or are you a whiskey person?) Humans are pretty stubborn about seeing things their way.
The final element is the ecology surrounding the evaluator and its tolerance of ambiguity and change. If the environment and the rational components of the culture have facilitated and rewarded what Kripke called the elaboration of cognitive frameworks (changing your mind), then there will be little resistance to the accepting that one individual may say a hire was "okay" or "decent" while another may say it was "a home run" or "great." The phenomenological bubble of the individual and the flexibility of the ecology will allow both opinions to persist and even be equivalent without the need to marginalize one or the other view.
So, you wanted to "understand how anyone can think this isn't a great hire" and here is your answer. Your "great hire" and my "decent hire" are the same thing view from slightly, but coexistent angles.