Holy War - Oxymoron

i think "holy war" is an oxymoron because when people say holy, it usually means something great, peaceful or heaven-like things. but war is like violent, killing, deadly action. so they are opposite meaning but it is said together. there are so many conflicts based upon different religions because i think people think that their religious believes are better than the others. and in some of the Muslim countries, they are trained and taught to die for their religion, and say they were told to commit a violent action. even though most of the religions are against killing people, i think people are being to selfish and thinks that their religions should be the best, so i think they are killing people of other religions.