War is neither "evil" nor "not evil".
War is a mechanism to gain things...
Sometimes the goal is power & conquest, other times the goal is liberty and freedom.... etc...
Some countries engage in wars with "evil" intent; think Nazi Germany.
Some countries engage in wars with "good" intent; think the Allied Forces that fought Nazi Germany.
There are two sides to war (sometimes more than two sides).
Sometimes those with "evil" intent prevail, sometimes those with "good" intent prevail.
If "evil" didn't exist, war also would not exist.
War is neither "evil" nor "not evil".
However, war is not "good".