His point was that cryptographic hash functions can be designed to be both slow or fast for different purposes. Key derivation functions and password-hashing functions like bcrypt and PBKDF2 are designed to be slow to mitigate brute-force attempts. But general-purpose hash functions like SHA-3 are not designed to be slow; in fact, you'd rather they be fast, because they're designed to be used in e.g. MACs.

In general, cryptographic hash functions are designed to be computed quickly, and key derivation functions are a special subset with greater difficulty requirements designed to be computed slowly. Your comment conflated the two, hence the parent's response.