"But how are they supposed to have 'stolen' magic?"... "It's mental, if you could steal magic there wouldn't be any Squibs, would there?"
-Ron Weasley (DH11)
Soon after the Ministry of Magic falls to Death Eaters (DH8), a commission is set up to keep tabs on Muggle-born witches and wizards. It’s purported mission is to learn about how Muggle-borns came to be magic-users. It requires witches and wizards to prove that they have at least one wizarding relative; otherwise, they are accused of “stealing magic” and will be punished and have no right to a wand. The head of the Muggle-Born Registration is Dolores Umbridge. (DH11, DH12, DH13)
The Ministry fell on August 1, and the Commission is up and running by the time Harry, Ron, and Hermione infiltrate the Ministry on August 4.
Similarities to real historical events make this even more sinister. Probably the most famous instance is the persecution of Jews in Nazi Germany. Similar efforts to control and eliminate minority groups have cropped up right up to the present-day. -BB