So Griffith basically changed the Earth while Guts was doing nothing on a boat. What the hell!?
The dichotomy of Guts and Griffith is a major component of the story.
It's ironic and I think it's meant to blur the lines between good and evil.
It raises the big "the end justifies the means" question. Wictionary says it well: Morally wrong actions are sometimes necessary to achieve morally right outcomes; actions can only be considered morally right or wrong by virtue of the morality of the outcome.