Sure, it’s more complex than just that animals have to consume energy to live, but it’s simple enough that we know the answer to the question. If we focus on plants that are best for humans to consume, it’s trivial to see that feedings animals to eat wastes resources.

You’re making a staw man. Growing crops that create scraps that we can’t eat is partially only done because of subsidization of those crops to feed animals. Also, we can eat the most nutritious parts. The cob and stalk of corn are not rich in energy. Sure, cows can eat them, but they have to consume a ton of them.

If we grow crops for humans to consume, we get significantly more energy out of it than if we grow food for animals. This is trivial. Argue against this if you’re going to argue. Don’t argue against something else that’s not relevant.