I think wars are generally fought when we are too weak to take the best option, or too stupid, or not competant enough to see it through.

World War I was fought because no one was smart enough to say "hang on, why don't we just deal with the guy who shot the Arch Duke and not rampage through Serbia when only one Serb pulled the trigger."

War may bring progress through necessity, yes, but it ties up resources and extinguishes lives. How many poets, philosophers, scientists and good honourable men have died in war? How many have come back physically and mentally damaged.

The only reason I would fight a war would be to stop someone else from fighting it for me.

Do I believe hummanity is good? Yes, but I also think we can be weak and stupid, which is no excuse to stop trying.