Pokémon is actually set in an alternate universe where Japan used its Pokémon to win World War II. After that the government began harvesting the natural resources of other countries, which is how everything is so technologically
advanced and free.
Nobody speaks about it because it would ruin the illusion of a perfect utopia. Since it was the war to end all wars, fighting is highly looked down upon which is why people have Pokémon battles instead.
Remember Lt. Surge? He betrayed America by giving Japan access to its power grids, in exchange for safe passage to Japan.