Sounds like tacos shouldn't be interviewing anyone as it's clear the lack of C knowledge surely makes any candidate an incapable one.
I've also seen Matlab shitheads who couldn't do it in C either, so it goes both ways.
The point of mentioning that wasn't to "neener neener" a recent grad it was to open the greater discussion you see here regarding CS trends.
Caltech is brutal and spending five years there without touching C seems... odd. How can you spend half a decade driving past the Jet Propulsion Laboratory on the way to Trader Joe's and not pick up the skills to get an interview with SpaceX?