War should be used as a treatment for longstanding unsolvable disputes. It is not a must. But when there is pre-motivated and ruthless suppression of its people by a ruler, the only way out is war.
When Bengali civilians voted for Bangla National Party of late Mujibur Rahman, the Pakistan govt. suppressed the Bengalis by sending army, fully armed with tanks and machine guns. Millions were uprooted and sent into India, resulting in a huge burden on our economy. Half a million were killed by the army. Almost all countries showed sympathy for the Bengalis, but none acted. India, unable to bear the burdens, went to war and created Bangla Desh. This is a clear case of necessity for war.
For some ailments, we can apply some ointments; for some, we should take pills; for some, we should get injection; for some, we need operation, which gives instant remedy from the ailments. War is like an operation.