I think this is when The Worm (or Adam or Omega) realises that his fans aren't just people who are outcasts and understand him, but people who like him just because he is controversial ( AKA the Beautiful People). He doesn't want to become one of them again like he did in Mechanical Animals, therefore that's why he kills everyone, because that's the only way his problem can be resolved.
I think this is when The Worm (or Adam or Omega) realises that his fans aren't just people who are outcasts and understand him, but people who like him just because he is controversial ( AKA the Beautiful People). He doesn't want to become one of them again like he did in Mechanical Animals, therefore that's why he kills everyone, because that's the only way his problem can be resolved.