Song in class symbolism (spoilers)

Not that the use of music in this movie is sophisticated but it is quite clear there is a connection between the main characters at Ms. Edmunds music class and the song Why Can't We Be Friends. It is all around their mood and friendship mainly from the point of view of the Jess Aarons:

The song of WAR "Why Can't We Be Friends". At this time in the movie Leslie beat Jess in running and that makes him mad at her. So lyrics like "Why can't we be friends" and "I called ya but you could not look around" make sense. Their is no reason why both of them not get along.

War drummer Harold Brown said about this song: "Because all of a sudden you find out we're more alike inside than we are on the outside. We started realizing that that's really important. You travel all over the world, you can't speak a lot of their language. But one thing they do know, they know your body language, how you may react."" they both come from different status, rich and poor, but as Brown said it is about the inside that matter, both of them connect at human level and this is what happen later.

and if we talk about song, use Hayden Panettiere, Miley Cyrus and other female teenager singer was terrible idea, not fit the plot at all.