The kill list in “ Is God Is ” is a short one: a single name, and not even a name at that. The sole target of Aleshea Harris ‘ incendiary revenge movie is credited only as “the Monster,” and really, he’s very much just a man. Men are the enemy here, but so are women, their children and anyone else standing between twin sisters Anaia ( Mallori Johnson ) and Racine ( Kara Young ) and their quarry: They long ago stopped seeing as human the estranged father who scarred them for life, inside and out, and so their belated mission to get him back takes on a mythically merciless dimension. Inhuman violence begets inhuman violence in “Is God Is,” a bloody, neck-snapping jolt of a film less concerned with moral justice than amoral catharsis.…