Where does that say it is an encryption algorithm? It is a hash function, there is a big difference.

SHA-2 is a set of cryptographic hash functions (SHA-224, SHA-256, SHA-384, SHA-512) designed by the U.S. National Security Agency (NSA) and published in 2001 by the NIST as a U.S. Federal Information Processing Standard. A hash function is an algorithm that transforms (hashes) an arbitrary set of data elements, such as a text file, into a single fixed length value (the hash). The computed hash value may then be used to verify the integrity of copies of the original data without providing any means to derive said original data. This irreversibility means that a hash value may be freely distributed or stored, as it is used for comparative purposes only. SHA stands for Secure Hash Algorithm. SHA-2 includes a significant number of changes from its predecessor, SHA-1. SHA-2 consists of a set of four hash functions with digests that are 224, 256, 384 or 512 bits.

SHA-2 is a set of cryptographic hash functions (SHA-224, SHA-256, SHA-384, SHA-512) ... ...
A hash function is an algorithm that transforms (hashes)

ryp·tog·ra·phy
[krip-tog-ruh-fee] Show IPA
noun
1.
the science or study of the techniques of secret writing, especially code and cipher systems, methods, and the like. Compare cryptanalysis (  def 2 ) .
2.
the procedures, processes, methods, etc., of making and using secret writing, as codes or ciphers.
3.
anything written in a secret code, cipher, or the like.