Newt creates the Register while working for the Beast Division of the Department for the Regulation and Control of Magical Creatures (FB).
This move was not unique. The Werewolf Code of Conduct was put in place in 1637 (PS16), and Dolores Umbridge was instrumental in the passage of restrictive anti-werewolf legislation that Sirius said made it almost impossible for Lupin to get a job (OP14). -BB
According to Scamander, werewolves have been shunted between the Beast and Being Divisions of the Department for the Regulation and Control of Magical Creatures for years. At one point, the Werewolf Registry and Werewolf Capture Unit were both in the Beast Division, while at the same time the office for Werewolf Support Services was in the Being Division. (FB)
Ahead of the release of any of the Fantastic Beasts films, Scamander's creation of the Werewolf Register is one of relatively few things we know about him. Since fans are already sympathetic and privy to the reality of the plight of werewolves, the prospect of a protagonist who had such an important hand in their persecution may be difficult to swallow. Rowling continues to show us how complicated things like bigotry and social injustice are, and it will be interesting to learn more about the brilliant who created the Werewolf Register. -BB