I think it goes something like this: (1) God created morality and cow-breeding, and (2) put the knowledge of it into humans [or, alternatively, the knowledge of morality was the result of eating the apple and knowing Good and Evil, I'm not sure], and (3) one of the important points of morality is that humans should have free will, and so (since God is moral) they do, and thus (4) they are free to practise immorality and cow-genocide.