Where "The Shadow" was effectively God's wrath, "The Punisher" is effectively man's wrath.

I suppose that it's not true justice, it's compromised justice in a fundamentally unjust world.

Where Batman hoped to destroy the corruption of Gotham with Harvey Dent and Commissioner Gordon; the Punisher would just shoot the cops. If your system won't tolerate ethical men, then an unethical man is the blowback against the system that it can't control.