The page gives solid rationale against PBKDF2: Although PBKDF2 is more widely available than bcrypt or scrypt, it doesn't offer the GPU resistance that we need

The page gives solid rationale against PBKDF2: Although PBKDF2 is more widely available than bcrypt or scrypt, it doesn't offer the GPU resistance that we need from a password hashing function. If you must use PBKDF2, make sure you use at least 100,000 iterations and a SHA2 family hash function. To reiterate: PBKDF2 can still be secure. It's the least secure of the acceptable password hashing algorithms on this page, so we aren't going to provide any example code.