From: RayCRP | #045 Does everyone not realize that the Kalos dex includes Pokemon that have existed in other regions? Sure, the Kalos-only Pokemon are new to us as a player, but from a regional perspective, many "old" Pokemon are also native to Kalos. Coincidentally, those are the native Kalos Pokemon in which Mega evolutions were discovered.
This is actually the correct logic and it's bothering me that more people don't understand it. So rarely do they attempt to use ingame logic to explain gameplay mechanics, but this is one of the rare times that they are.
Hey man, LlamaGuy did encrypt the passwords. With what? ROT-13? -CJayC