In a document titled “Blockchain Technology Overview” from the National Institute of Standards and Technology under the US Department of Commerce, authors Dylan Yaga, Peter Mell, Nik Roby and Karen Scarfone claim that “technically,” the perception that BTC is the genuine version of Bitcoin is incorrect.
“When SegWit was activated, it caused a hard fork, and all the mining nodes and users who did not want to change started calling the original Bitcoin blockchain Bitcoin Cash (BCC),” they write.
“Technically, Bitcoin is a fork and Bitcoin Cash is the original blockchain. When the hard fork occurred, people had access to the same amount of coins on Bitcoin and Bitcoin Cash.”
This has been corrected by the authors already, the document now states that Segwit was a soft fork.
Besides, why would anyone take NIST seriously? When choosing the signature scheme for Bitcoin, Satoshi Nakamoto deliberately ignored NIST's published recommendation of the type of elliptic curve to use for signing transactions. It was later discovered that Satoshi was very wise to do so; NIST's recommendation was an ECC curve with security flaws, while Satoshi's choice is demonstrably secure today.