It's simple enough, really: Pokemon started its Japanese broadcast in the late 1990s, before the fansub scene was equipped to handle series of that length. So no fansubs. Pokemon never got a dual-language DVD release in R1, thus no dual-audio rips are possible. That means the only version available is the English-dub TV-rips. Same goes for Digimon, Yugioh, and other kid-oriented series. Mostly, the only Japanese/sub episodes out there are the "controversial" ones that never made it to US TV.
