I got a Japanese thundurus I can trade it with your celebi PM me if you are interested.
current games - X & Y
also White2 and HeartGold but not play them at this time.
3DS FC: 0104-0278-1948
They do it to trigger fan-fictions. Fur da lulz. Cuz you know how those fan stories can get... *shudders*
So the writers put things in the show just so they can read our screwed-up fanfics? That explains everything