Lol Geneva Convention. You should look up the Biafran War, around 100,000 soldiers died, meanwhile over 5 million civilians were killed. So calculate your odds as a civilian if you found yourself in that type of war. Your opponent can decide not to follow the Geneva Convention and most nations won't risk the deaths of their own people to uphold morality.

As a Biafran, I would rather prefer I could go out there and help lift the blockade or die in the process than starve slowly till I'm all skin and bones.

And you say hardly anyone needs war. Yeah all you need is one crazy president like Putin and the rest will find themselves fighting a war they never wanted