He woke once more to external reality, looked round him, knew what he saw—knew it, with a sinking sense of horror and disgust, for the recurrent delirium of his days and nights, the nightmare of swarming indistinguishable sameness. Twins, twins.… Like maggots they had swarmed defilingly over the mystery of Linda's death. Maggots again, but larger, full grown, they now crawled across his grief and his repentance. He halted and, with bewildered and horrified eyes, stared round him at the khaki mob, in the midst of which, overtopping it by a full head, he stood. "How many goodly creatures are there here!" The singing words mocked him derisively. "How beauteous mankind is! O brave new world…" (15.3)
John resorts to thinking of the bokanovskified twins as animals, but this is a coping mechanism. To face the thought of multiplied, identical humans is disgusting and unbearable, so he mentally strips them of their humanity.