It's a question of proper case, which students don't learn anymore because few English teachers show students how to diagram sentences or how to memorize grammar rules. Furthermore, few students take Latin, which also emphasizes the importance of case agreement.
"Him" is objective case, which is used following a preposition. For example, "Give it to me" ("me" is objective)--and, obviously, "Give it to I" would cause heads to turn!
Oh, and you speak of animus. Are we wrong to have animus towards Al Qaeda or Nazis or Communists? We can identify the whys and whats of their evil, but in the end we also have great anger or hatred towards them. Is this wrong?
In many ways, cheating and then passing another man's child off to someone you claimed to love and cheris is a greater sin than killing strangers who don't share your beliefs.