Oxymoron "Holy War"

"Holy War" I believe is an oxymoron because the word holy by many peoples beliefs means peaceful and calm and without stress or perfect. But war seems to be the complete opposite from that. War to me means pain, suffering, hardship, chaos, and many other bad things which have very different and sometimes opposite meanings then the words that describe holy. I also think the reason that there are so many conflicts around the world that have to do with religion is because the people that practice the religion find it to hard to accept that other people follow other religions. And so they go to very high lengths to try to convert or protect their religion. Another reason that religious wars are fought even though the religion tells against killing is people don't always take comments or actions as other people do so they may react in a way that triggers a war.