You know what? Godo nailed it... He completely eviscerated Gut's two years of suffering into nothing! Sure he is doing good things fighting those things, but he wasn't doing it for the right reasons. Does Guts ever learn? The very thing which drove him away from Casca was not too dissimilar from when he left the band of the hawks!
I'm with Guts... I don't believe in destiny and I sure as hell don't think it's productive. Guts made that choice despite ample warning and by some twisted casuality he paid a steep price for it.
But Guts doesn't have the luxury to comtemplate what a fuck up he made, he needs to rescue Casca.