There can also be a bit of an attitude, like the person is thinking "of course this is good, I went to Stanford". But maybe that's my imagination. Another explanation is that these people are just so good that they are able to read messy and convoluted code no problem, and us mortals need to step up our game.
On the other hand, these people would easily be able to reason about complex performance and security issues beyond me. I think that the hardcore CS issues are a science, while writing clean code in a web framework, browser, and API design is more of a craft.
If you hire too many computer scientists, your code base could be full of fascinating technical tricks, but creaky and hard to work with. Too many craftsmen, and you'll get stuck on simple problems. It's a balance.
EDIT: Downvotes? Please explain. Perhaps I am not able to fully comprehend the issues at hand.