The antidote of oppression is not the Index statisticum prohibitorum, but quite the opposite, education, and in particular educating about how different each and every one of us is, and yet it doesn't take much to get along well.
(Or, of course, simply pass a law that entitles them to deport or hold indefinitely anyone who can't prove they're a real Ayrian with only the papers they have on them at the time)
Remember; fascists don't believe in things because they are true, but because they are a means to an end. Their ultimate goal is authoritarian control, and an administrative mechanism is far more effective toward that goal than a scientific one.