>50% of working programmers can't write a for loop? Does that square with your experience outside of interviewing?
Not 50% of working programmers, but of the programmer applicant pool. The applicants who can find jobs quickly aren't in the pool very long, and so it's dominated by the fakers and those who otherwise shouldn't be there. ... Which should make the reported phenomenon a little more believable.
50% of working programmers can't write a for loop? Does that square with your experience outside of interviewing?
I don't quite buy the whole fizz-buzz story, though I don't have an adequate explanation for what could cause these kinds of failure rates. Something seems very off.