"Who the hell cares you assholes!!"-Angryman
War is two or more opposing forces that like to fight it out on the battlefield by shooting guns, blowing up buildings, starting a whole mess of problems later in the future.
The reason for war is obscure and also unimportant because the dumb behavior of humans causes them to get into these scuffles and do not know when to shut down the whole thing.
However, the American Civil War was about ending slavery in the American South and sending the Democrats a message that they cannot enslave people and make them do their dirty work.
This wasn't always the case about wars some of them were just used to fighting for the sake of fighting that is what humans do best sometimes but they can resolve problems.
Starting a war about a rubber chicken is not a good way to get a point across to the world that one nation is disgusted with the current government.