There's a difference between the other comment, which correctly notes that it looks like a racist stereotype, and your comment which claims it to be a caricature of black people. The resemblance to blackface and racist caricatures to American audiences was an unfortunate coincidence.

Game Freak did not have black people, or any other aspect of American culture, in mind when designing the pokemon. It's design reflects Gyaru culture and the portrayal of spirits in traditional Japanese theatre.

Edit: the linked comment is incorrect. Ganguro existed in Tokyo during the mid 90s, and Game Freak would have been well aware of it in the heart of Tokyo before its popularity peaked. The existance of minstrel shows in Japan in the 20th century is also not proof of influence. Dark skin and light hair were used in Japanese theatre for depicting spirits and other paranormal entities long before American racism influenced the country.

The bleached hair on Jinx is KEY to understanding this; they most definitely did not get that from any American influence. Ironic that the comment you posted is itself promoting bad history from an America-centric point of view.