TLDR: Japan's now full of raccoons because an anime (Araiguma Rasukaru) made them look like fun to keep as pets, until you have to let them go into the wild because they're getting too aggressive.
But Japan's not really full of raccoons. I've never seen a raccoon in ~4 years here and I've seen 30+ wild tanukis (up to 10 or so could have been the same ones). It also states in the article that Hokkaido has been killing off 2,000 raccoons per year because of the agricultural loss due to raccoons. With that being said I've only seen 2 wild raccoons in America in 25 years so maybe they're just much better at hiding than tanukis.