We do have animal welfare regulations. Whether those are sufficient, appropriate, compatible with ones ethical framework or view of how they (whether "livestock", "pets", "wild", living beings generally, etc.) are to be treated, is besides the point, we do have some restrictions in place.

We (as in many major legislators and most humans) have recognised animals to be conscious beings, deserving of certain protections. Anyone who asserts LLMs to rise to the same must be accepting of similar protections being applied to such models.