Welcome to the human race...
+1
WARNING: "Heathers" spoilers below
On one level, you can blame executive meddling for changing the original ending where J.D. dies but Veronica lets the bomb kill everyone anyway so the final scene ends up taking place in Heaven where everyone's having fun at prom (in keeping with J.D.'s line about how that's the only place where everyone can get along).
However, in the case of this ending I think it's more a matter that Veronica confronting J.D. as she does is what makes him realise that his mission has been based more on his own personal issues than the faults of any of his victims or society in general - in realising he is the bad guy, he decides to use the bomb on himself.
On one level, you can blame executive meddling for changing the original ending where J.D. dies but Veronica lets the bomb kill everyone anyway so the final scene ends up taking place in Heaven where everyone's having fun at prom (in keeping with J.D.'s line about how that's the only place where everyone can get along).
However, in the case of this ending I think it's more a matter that Veronica confronting J.D. as she does is what makes him realise that his mission has been based more on his own personal issues than the faults of any of his victims or society in general - in realising he is the bad guy, he decides to use the bomb on himself.