Lyric discussion by TusChan 

Cover art for Mark David Chapman lyrics by Mindless Self Indulgence

The meaning of this song to me is pretty much a combination of things that have been said here already. This song is basically about how all bands sound alike to each other, and that bands that actually make an effort to be different and care about the music are drowned ou by the hordes of clones flooding the music industry. He then focuses that specifically on emo / boy bands with little talent or originality that sell mainly from being "hawt".

The purpose of inclusing Mark David Chapman in this song has little to nothing to do with Lennon, it has to do with what Chapman did and why. Chapman killed Lennon because he thought he was a phony that everyone was following. Jimmy isn't asking for people to kill the bands, he is simply stating that if Lennon was around today he would want to kill all of these generic bands because they are all phonies.

As for "I'm part of the problem, not the solution", to me, even though this is probably unintentional, he is saying that he is also guilty of selling out, which is sort of true, whether he realizes it or not. After all, two-thirds of the album "If" sounds just like the generic bullshit this song is making fun of.

Finally, the song also is saying that when MSI is gone, other bands will simply take their place.

My Interpretation