He wanted so bad to blame someone.
It was Norman's fault. That was easy, because Norman was one hell of a bastard, and poor Harry had suffered so much for it.
Really though, it could have been Harry's fault too. So Harry's life hadn't been great? Whose was?
Did that mean he had to do drugs? Make the wrong choices?
Did it mean he had to follow in the footsteps of his father?
It would be so easy to blame Norman or Harry, but he knew the truth.
Despite the harm it inevitably caused others, Peter Parker needed to be Spider-man, and Harry Osborn had paid the price.
Again Peter Parker was the murderer of someone he loved.
And as always, he was the only one at fault.