>>58107433It's not really the same thing.
If a trainer dresses to resemble their Pokémon, it's not a problem.
On the other hand, when the Pokémon takes on the traits of a trainer, it's different because it's no longer its own independent entity.
Irida and Adaman resemble Dialga and Palkia because they worship them as gods.
Dialga is its own entity, which initially has nothing to do with Adaman. It was Adaman who decided to imitate it.