I don't have any definite info from anyone who worked on the show, but based on what I've read, my guess is that the American actors just wanted to avoid dubbing the song. None of them were happy with their singing abilities, and they talked through most other songs, or even left them untranslated (the owls' song). They probably felt they couldn't do justice to the song, and there is no way they could leave it in Japanese, so they opted to cut it out.

--Previous Message--
: any reason why this bit wasn't shown on the
: american version (contributed for NBC)?
:
: you know the song with a jazzy beat with 4
: black leopards that plan to steal dreams or
: something
: i found this data on the Kimba W. Lion
: website
: