it doesn't hold water. first you should define Hindus as something
It's a basic tenet of anthropology that religions are defined by observing the beliefs and practices of the people claiming affiliation. Religions are not defined by an outsider imposing his expectation of a rigid dogma. Within Hinduism, there is an immense variety of beliefs and practices, some of them mutually contradictory to Western eyes, and that's fine by Hindus themselves. Even if most Hindus believe in the supernatural, others do not, and all of that coexists within, because inclusiveness is an value that most Hindus hold to.
Someone outside this religion (or outside any culture being studied in general) has no right to point at one person claiming an affiliation with Hinduism and say that "he is a real Hindu" and point at another and say "he is not".