Why does the youth feel bitter and betrayed after the battle?

After the battle, Henry thinks of his comrades, dressed in blue. They won. The thought makes him bitter. He, the enlightened one, had fled because of his greater perception. They would not see it like that, however. He thinks about the derisions and insults he will have to bear upon returning to his regiment. He pities himself, as if an injustice against him was committed.