What happens to the Alternate History? Without Stocke, the Ritual can't be completed there.
I just assumed that the AH collapsed into the Standard / True History. Stocke threaded between the two timelines enough that they might have just merged somehow. Or, you know, everyone in the AH eventually died after the desertification enveloped Vainqueur. But that would be sort of depressing, you know?
Open the White Chronicle before you fight the final boss. Notice how the timeline you're in is in the middle? It can be said that Stocke had indeed threaded the Standard and Alternate histories together, creating the True Timeline mentioned oh-so-long ago.
Red Oni isn't always indicative of personality; it can just as easily refer to behavior, especially compared to the likes of Eruca and Raul. Stocke's actions (jumping headfirst into danger, quicker to go with his gut, etc.) suffice to characterize him as the Red Oni in most comparisons, while his initially cold and withdrawn personality characterized him as a Stoic. It's actually quite possible for a Red Oni to also be The Stoic or for a Blue Oni to be Hot-Blooded (though the latter would be more difficult to successfully pull off).
That, and the relationship where he's the red half of the pair was under a different name, and with different memories. During the game's time period, when he seems to be much more withdrawn, he plays Blue to Rosch more often than not.
So is everyone a massive hypocrite, or am I missing something? Later on in the game, it's revealed that the Ritual requires a sacrifice to be completed. Everyone reacts to this with shock and horror, and the conversation culminates in Stocke saying, "No matter how you look at it, it's wrong." Perhaps it does seem cruel, but none of the characters are that torn up about the full-scale WAR going on. How is sacrificing a single person in the name of saving the world worse than sending countless troops into battle in the name of expanding Alistel's territory? That whole cutscene just felt totally out-of-character for everyone.
The way I see it, it's because people signing up to be troops have a choice about it, they made a decision to risk their lives, while the Ritual basically requires someone to be a sacrifice with no option on the matter. Worse, it's not just some random person grabbed to be a sacrifice, it's someone who was raised for the purpose and only the purpose of being one. Less dangerous to bystanders, but in terms of being morally horrible... The war still isn't that great for civilians, who didn't have a choice on the matter, but from the point of view of the non-power-grabbing governing parties, they are trying to defend their civilians. Even for those who initiated fighting, they're doing it to get more arable land so they can support their population. So while I doubt any of the main characters are happy about the war, it's understandable why they aren't as upset by it.