It's working so far for Russia. It worked for Germany in WWII until the US stepped and fought our way through Europe.
If you see a certain group as your sworn enemy for life which should be destroyed at all means possible -- then you will never have peace. All you can have is war.
The long term result of justifying the mean is always the subordination of the individuals, you migrate from a democratic society to totalitarian state.
I feel it's safe to say that no society prefer dictatorship to democracy.
So you won (maybe), your life is worst, you have no freedom anymore.
Beside you say in some case war is inevitable because there is too much hate. I don't agree, people (individuals) can be so hateful that war is inevitable but populations always aspire to peace.
Even totalitarian state always have to justify the war by pretending they're the one merely defending, being attacked because this desire for peace is so powerful.
Beside, killing without distinction combattant and civilians didn't work, see the result of the American Afghanistan war.
Even during the war, 99% of the country was to the hand of war leaders and talibans because everyone hated Americans. Guess why.
It took only a handful of days for Talibans to defeat the American sponsored 'democratic' gouvernement.