Not just genocide but eugenics.

They will genocide anyone who doesn't fit in whatever their definition of a perfect human being is.

Your elderly mom who has a disability? Gassed.

Your partner, who happens to have some link to a race of people they don't like? Gassed. (And your children, possibly you too for fraternizing)

You look a little different for no apparent reason? Gassed.

It's almost like old school witch trials in nature where they just make up shit with flimsy justifications to exterminate you.