INAL and it’s been ages i studied copyright law and it’s also depend on country(in this case, it’s japan company vs japan company), but plagiarism only catch anything on the surface, they have no reach on the concept or idea or thought itself. The work itself also have to be very, very close to the original artwork, otherwise it can considered derivative and is protected by copyright law. In this case, Palworld have their own idea and twist on their monster even though it looks like the original work they copied, and the gameplay are mostly unfamiliar from the original work. They make it close enough to evoke the same feeling people have toward pokemon, but different enough to get away with it.

This is why Nintendo did not try anything against Genshin, even though Genshin took BOTW and add some of their idea. And this is also why you can film your own version of lion king, but the character is all bugs or something.

Personally i think Pokemon Company will not take action, the statement could just be something to make the fans stop bothering them. But i’d like to proven wrong.