Quote 7
"Strumpet! Strumpet!" he shouted at every blow as though it were Lenina (and how frantically, without knowing it, he wished it were), white, warm, scented, infamous Lenina that he was dogging thus. "Strumpet!" And then, in a voice of despair, "Oh, Linda, forgive me. Forgive me, God. I'm bad. I'm wicked. I'm… No, no, you strumpet, you strumpet!" (18.64)
Take a look at this: John wishes that it was Lenina he were striking. Because she's a "strumpet"? OK, yes, but also because striking her with a whip is the closest he'll let himself get to having sex with her. In a novel with a very, very fine line between sex and violence, there's little difference between them.
Quote 8
"Strumpet!" The Savage had rushed at her like a madman. "Fitchew!" Like a madman, he was slashing at her with his whip of small cords. (18.92)
Exactly.
Quote 9
Drawn by the fascination of the horror of pain and, from within, impelled by that habit of cooperation, that desire for unanimity and atonement, which their conditioning had so ineradicably implanted in them, they began to mime the frenzy of his gestures, striking at one another as the Savage struck at his own rebellious flesh, or at that plump incarnation of turpitude writhing in the heather at his feet.
"Kill it, kill it, kill it…" The Savage went on shouting.
Then suddenly somebody started singing "Orgy-porgy" and, in a moment, they had all caught up the refrain and, singing, had begun to dance. Orgy-porgy, round and round and round, beating one another in six-eight time. Orgy-porgy… (18.98-100)
Notice that John says to kill "it," not "her." Huxley himself calls Lenina "that plump incarnation of turpitude." While John is beating her up, he's really trying to beat up all the dirtiness and promiscuity of the new world.