You're missing one key thing - by the time we see the candidate they've given us a resume that says that they can and have programmed some actual things in some actual langauges. How do you explain their inability to then do some trivial thing (more trivial than fizzbuzz even) in the language that they've already claimed skill in?

I could be wrong, but these simple tasks seem to help distinguish "hung out on a team that did those things" or even "has been stuck in meetings 38 hours/week for the last 5 years and is startlingly good at powerpoint", when those are not what we're looking for.