[oconnor663]

This is a common misconception, based on the difference between password hashing and other general uses for a cryptographic hash. Password hashing is special, because we want to protect people who pick terrible passwords, so we need guess-and-check to be expensive. But for most other use cases, like say HMAC or signing, the number of possible inputs is so astronomically large that guess-and-check would be impossible even if each guess was e.g. just a single add instruction. This distinction is why we say never to use a general purpose hash with passwords.