Lots of Happy Catholics went off to Invade, kill and burn to the ground lots of cities full of Happy Catholics (who weren't so happy when they got gunned down, by those other happy catholics)!
What was Germany upset about after WW1? (lots of germans seperated from "the fatherland" and those germans were upset, they wanted to be re-united)!
What drove the Serbs to set off WW1, by assassinating the heir to the throne of the empire that would rule over them? They hated him because he was trying to placate them; they wanted serbians united, not "pacified," by some "liberal reformer." They didn't care what the duke's religion was! They weren't out to unite Catholics; they were out to unite Serbians!
Wake up and smell the coffee (along with the roasting bodies). Race, at least in practice, trumps religion and it does it by a mile!
Forget it; that's just the way it is, some things will "never" change.