This is the worst thing about this sort of "IQ dick-waving contest" culture, to me. I'd be fine with doing ridiculous CS Theory stuff in interviews, if the job was about doing that. I love that stuff, when my mind is geared into the right mode, and a job that required a lot of it would give me the ability to leave my mind geared into that mode. Instead, my mind has downshifted into the CRUD-dev gear from years of disuse, and you're asking me to shift it into high gear for the interview... only to shift back down for the work itself.

I get that every small company wants "the best and the brightest" in order to have more value on the table under acquihiring conditions, but there's really no reason that the person programming Facebook's Android frontend view-controllers needs to know how to answer doctorate-level category-theory questions.