According to Bulbapedia, it seems as though the English-language dub of this episode wasn’t released in order to avoid possible blackface comparisons and criticism.
During the 2000s, the character Jynx had to be redesigned after the character’s appearance was criticized as negative racial stereotypes.
As Bulbapedia and Gamerant (via Yurukuyaru) explain, Ash dresses up like a Passimian in the episode.
Since then, the episode’s English dub has not been broadcasted in the U.S. Rather, it was skipped entirely.