If you are to take philosophical books, written by people such as the Qu'ran, the Torrah, the Bible, etc and try to take them word by word then, yes religions can equal disharmony.
If on the other hand we understand the there is only one Great Spirit, of which we are but a little part then, we would understand we are all the same. The same energy flows throughout all living things.
The differences in religions arise from cultural backgrounds and not spiritual backgrounds. That is why texts should be understood for what they are: books written by wise people to teach us morals and values in order to be able to live together in communities/societies.
The Great Spirit never published anything. It just is. May it guide our path when we are lost!