In the grimiore it says they are female I know but they are called Wizards in game and the grimiore cards still classy them as Wizards so call them what they are they are Wizards not witches
-
The fact that I have a Choleric Dragon SRT-49 with the "Malleus Maleficarum" perk, named after the historic book known as "The Witches Hammer" and that deals additional damage to Hive wizards, suggests that even Bungie think of them as witches