http://youtu.be/9_9x9m8F1b4I think you got it backwards. "Billy" just wanted to be loved and he was willing to decapitate the head of society if that is what it took to get accepted by anyone. It's how every mentally ill megalomaniac feels.
___________________________________________________________________________________________
DR HORRIBLE
Here lies everything.
The world I wanted at my feet.
My victory's complete,
so hail to the king.
CHORUS
(Everything you ever... )
DR HORRIBLE
Arise and sing.
So your world's benign.
So you think justice has a voice
and we all have a choice.
Well, now your world is mine.
CHORUS
(Everything you ever... )
DR HORRIBLE
And I am fine.
.....(musical interlude)...
DR HORRIBLE
Now the nightmare's real.
Now Dr. Horrible is here!
To make you quake with fear!
To make the whole world kneel.
CHORUS
(Everything you ever.... )
DR HORRIBLE
And I won't feel...
BILLY
...a thing.