The sectarian concept of god is prevalent everywhere by propaganda but the substance of God is in everything and it is for every one.
The sectarian concept of god requires history and on other hand the substance and experience of God goes beyond history.
Even when Param Brahman descends as an Avatara, people get stuck by what He does rather than the purpose behind what He does.
The historians question the action but the substance seeker experiences the purpose. Hence they see no duality between the action of an Avatara and his purpose.
Sri Krishna and Sri Rama, when they appeared defined the character, qualities and the cause of coming together with the consequences of their descent.
The historians see facts, the poets see the flow and the intellectuals see the flaw, but the substance seekers are floored by experiencing the substance of God.
God's Avatara is not for creating history rather it is to sensitize the human being of his overwhelming presence within and without.
The great teachers of dharmik traditions have summoned us to experience God by personally developing a relationship with Him.
Some one else's experience is a theory for others, hence we need to experience God.
Dharmik traditions say there are different kinds of proof for God's existence,
direct perception, hypothesis and the sabda or sruti. The highest is the sakshatkara or direct experience of God by inner science of Sadhana and grace of the very substance who we want to experience.
Therefore the Sri Krishna and Sri Rama appear to give us their essence which is beyond history.
Their appearance is not to prove their existence but to facilitate our experience.