I think we should make a distinction between animism and pantheism.
In animism, the concept of duality is not conformed yet, reality is a pile of forces without any categorization that conflict among themselves without any specific order.
Dualism is the result of categorization of phenomena, and brings a notion of order and movement in a dual division of substance... but, what conforms the laws of this interaction?
Pantheism is the notion of a God that gathers in His own nature the opposites, their interaction and their sum. (In daily life you find a lot of deluded 'pantheists', but that's not the guilt of the concept, again)