Upanishad: God is the first teacher, incarnation is establishment of lineage of Gurus. Upanishad would say that Srirama Krishna taught Brahmahana, and passed it down to Pavitrananda, and Pavitranandhi passed itdown to you. The avatar comes as a destroyer of doubt, as powerful demonstration of the truths of religion to us. Advaitic approach or the Buddhist, especially Tibetan Buddhist approach survives all these atheistic critics.