I would say that, given that it’s never ok, it is part of English grammartical rules. In German they actually use two different words for when a human eats or when an animal eats, it’s not unprecedented and there’s no need to lend any credibility to the usage of the word “it”.
There is a single precedent I can think of, which is that with some regularity I see infants/newborns referred to as “it”.
A mindset from the before (antibiotics) times. Babies used to die quite frequently. So much that in some cultures babies weren’t named until later in their life, not during pregnancy as it’s custom today. So they were kind of an out there thing, that wasn’t baptized and named yet, they were an it. They were “the baby”. No different than a dog or a turtle, they might die without a name, given an unmarked burial. And off to the next pregnancy. Still a tragedy, and people did mourn and suffered the loss. But not to the same degree of modern, western medicalized, pregnancies were almost every single baby born is expected to at least survive to infancy.
