https://slate.com/culture/2018/07/disney-xd-pulls-pokemon-episode-possibly-over-blackface-concerns.html

A Pokémon episode won't air in the United States for the first time since 2002. Disney XD has yet to respond to the yanking of the Pokémon Sun and Moon episode, but fans wonder if the episode was pulled because of its use of blackface.

That's absolutely why it was pulled and it isnt the first time. There are 5 episodes officially banned in North America that we will never see here. Aside from the porygon episode, can you guess why these other episodes are banned?