So it’s made of shit, right? And shit is an animal product. But barring a night of drinking or a particularly aggressive burrito, shitting does not harm the shitter; it’s beneficial and required. Also the animals in question can and do consent, does that make it vegan?
The interchangability of atoms isn’t the concern, but whether the food contains the animal proteins or other substances which a dietary vegan is avoiding for whatever reason.
I mean, proteins are complex structures made up of atoms, so rearranging them into a different structure would make them no longer a protein molecule, animal or otherwise…