Apt remarks by philosopher Paul Schofield (Bates) on Twitter; a couple of highlights:
The ad is written with a specific candidate in mind, who the department intends to hire. That candidate is not you.
The department thinks you're too much like, or not enough like, the other members of the department (somehow, both of these are reasons for throwing out a candidate and you never know which it is when you send an application off).
There's another candidate on the market exactly like you and departments are picking between you and that person, perhaps arbitrarily or perhaps on the basis of some leg up that that person has. You are otherwise perfect, but this person's existence ruins your year/career.
Everyone loves you except one member of the committee, and as unfair as maybe that person is being, it's easier to find a candidate that everyone likes than it is to fight with one's colleague. Nothing you could have done would have changed this asshole's mind.
The committee illegally discriminates against you.
A committee member totally misreads your application and eliminates you. No one protests because they all want to go to lunch. You receive the rejection and assume it's because Prof. X disagreed with the footnote on p. 27 of your writing sample.
A member of the committee has a preferred candidate and it's not you. You are serious competition, though. So the committee member tries to take you out early. Others see what's going on, but don't want to fight with this asshole and, again, want to go to lunch.
