I imagine the Derby theme and rejection process thusly:
someone at woot thinks of a theme.
someone else writes the contest writeup, which is an imperfect description of the theme (mabe they don't understand it exactly anyway)
the rejectorator rejects designs based on some arbitrary criteria, which is never described in the derby discussion threads, and only vaguely hinted at in the rejection notice. the rejection criteria doesn't depend at all on the contest writeup, so there's no way for designers to know where the lines should be drawn.
so rejections are hard to understand, confusion and bitterness reign. world ends on an unhappy note. the end.