Simplest explanation is that they are Pokemon with human characteristics. The implications of this is both subtle and complex, and I intend to lay out my perspective on them- Don't take it for gospel, they are merely the assumptions I'm operating under in my stories until the community at large overrides me- if you like the ideas, by all means, please use them! Yes, generally, Pokemorphs are omnivorous (again, human traits...), while some have specific dietary needs or preferences, they can eat all the same things humans can, and Pokemon are the only source of meat. Very well, thank you!