Frank was trying to get the people who not only did this to the world,
but who had been doing evil to the world for a long time. A group known
as The Coven. A word that means an "assembly of witches."
When Frank finds them, they try and tell him that they can save the
world. But Frank knows that these people would do the same thing all
over again to the world. Frank kills them."
This story does take place within the normal Marvel universe. It is not a "What If" story or an alternate Earth story.
Frank: "Once upon a time there was a bunch of evilf**ks Hardly anyone knew, because they were so good at keeping it quiet, but these particular evil f**ks owned the world. And they made the world a cruel and terrible place. They ran the great industries that poisoned the air. Their businesses turned whole countries into slaves. The money they made could have fed and healed the population of the earth twice over, but all that they could think to do with it was hoard it. They got away with it by being expert salesmen. These were men who could sell anything to anyone. They made puppets out of presidents and started wars for profit. Eventually, they came to believe that there was nothing that they couldn't do. And so one day... inevitably... they pushed the planet's luck too far."
"After the Twin Towers collapsed, they closed a lot subway stations in the neighborhood. For repairs, most people figured. For cover while they sank a bunker ninety floors down, was the truth."
"I blamed evil men...the parasites who preyed on human weakness. That weakness was a feeding ground that stretched beyond the infinite. The evil that it feed would never end. So I decided neither would my war."
"Oilmen and generals. Computer billionaires and senators. Captains of Industry. Teach called you the Coven. He said you wove a spell that lasted from the second World War to the third."
"Expert salesmen. They could sell anything to anyone. Except me."
"And that...well that's all I wanted to say. Do what you will."
---The Punisher: The End, Garth Ennis