4. Fighting
This is truly what Pokémon is all about: battling. Sure, you can breed them or show them off in contests but none of those activities are required. You can't catch the eye of another trainer without being coerced into battle. And while the idea of battling creatures has few scientific inadequacies it does harbor moral implications. We can argue on and on about why evolution and breeding works in ways within the games that could never work in real life, but we also can't forget that there is absolutely no way these fighting conditions would ever be accepted. Unlike in the Pokémon universe fighting between animals doesn't simply end with one side fainting and being subsequently revived at a special hospital. There's a reason this stuff is banned; it's gruesome and it's cruel and it's nothing like what you see in the games. Focusing less on morality there is more reasoning as to why the concept is unrealistic. Pokémon gain experience through battling and this is what allows them to grow. While the idea fits an RPG game it certainly wouldn't make any sense in any other setting. Furthermore, the idea of growth through battle doesn't explain in any way how Pokémon grow in the wild. Do they stage their own battles so that they can gain experience? Are random encounters enough for them? There's really no explaining it as there's nothing real about any of it.