The Buddha himself points this out in the Maha Cattarisaka SUtta, MN 117. He calls the belief-centered ethical systems such as karma/reincarnation "right view with defilements" (sammaditthi sasava), and distinguishes his own Noble Right View from these belief-cantered ethics.
This word "sasava" is significant here -- its root is "asava", which is translated as defilememts, pollutants, taints, fermentations, effluents. These are the same "taints" or "effluents", etc., that the Buddha talks about elsewhere, and he declares the goal of the path is the ending of the asavas. The Buddha defines the asavas as sensuality, becoming, ignorance, and speculative view, all of which we can see are intrinsic to ontology/belief-based ethical doctrines such as karma/reincarnation.