The Concept of one God need not be threatening if we all understand the intent behind the word "One God". It is extensively used in the monotheistic traditions, it is not opposed to "many iconic representations" of God, and rather it is the oneness of universe, oneness of creator and oneness of humanity. When there is oneness, you would feel the pain for the rape victims in a remote village or pray for the people who are being washed away in floods. It brings the humanity together.
In Judaism and Islam there is an emphasis about no God but God, it is stressed to make the point of oneness with the creator, so we can feel the pain of other humans no matter where they are. It avoids the apathy that they are worshippers of XYZ God and their pain is not my pain. Which Hinduism titles as ekantha or Vasudhaiva Kutumbakam or the other traditions call it one God. Reverend Moon, whom I admire, calls "one family under God”. We are seven billion unique beings God has intentionally created us to be different, look at our minds, our thumb prints and DNA's, each one is unique, if we can learn to respect the God given uniqueness of each one of us, then conflicts fade and solutions emerge.