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.
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.