People, ads should have the tone of THE MOVIE not have a completely different tone altogether! If it doesn't, it is false advertising because, by doing that, they are suggesting the movie is completely different! Also they could've shown other clips while playing, I don't know, the Busa music, the Simba climbs up to Pride Rock music, or other big, bombastic music (you know big and bombastic which is the tone of the movie).
Also not all 90's ads for movies were campy or comedic. I mean look at this spot for The Shadow (which came out the same year):
http://www.youtube.com/watch?v=EG0wojmRvVIThat's not that campy. OK so maybe it's a slightly different target audience (though those in this movie's age group probably saw it regardless) but still it's not like all movie ads were comedic and campy during the 90's. The only reasonable explanation I can see is DGFone's explanation that they wanted it to be seen as any other Disney movie.
Though there was this trailer in 2002 which did implicitly state it as a comedy (the narrator refers to mostly every character, even the non-comic relief characters, as "the funniest animals in the jungle"):
http://www.youtube.com/watch?v=COx3pDHT5-8