Yet, it was not a war between ideologies, but a war of selfish individuals, a fight for territories and power. In order to be successful all those individuals had to have followers and in order to gain them they had to poison the mind of the people. Simply, by propaganda. History is full of examples. Like the other animals, humans are social animals.
People ask for leaders and leaders ask for followers.
It is much easier to belong to an ideology, to some nationalism, to a party or a soccer club than to be independent. If you want to be a successful leader, you have to poison them with hate. Any kind of hate would serve the purpose. If you are a leader of the eastern state of Germany, tell your German people that the other Germans are nazis who want to destroy their state. If you are a leader of the western state of Germany, tell your German people that the other Germans are communists who want to destroy their state.