Why should Greek mythology be taught and not Hindu mythology?
People of European descent learn the history of their culture. Classical mythology is part of that history. Western literature and art is scattered with references to myth, so a passing knowledge of the subject is useful for cultural appreciation. Naturally Indians will study Hindu mythology as part of their tradition, and the Maori of New Zealand will learn theirs, and the Japanese theirs, and so forth. Its not unfair, just appropriate for the culture. You would not really expect Indians to learn Classical mythology since it is not relevant to their traditions and culture. Hindu mythology is also more complex since it is part of a living religion. So it is more comparable to studying Christian stories or Buddhist stories in school, which would earn some ire people who are opposed to religion in schools. Although, that said, it would be nice if they did teach anthropology (the general study of other cultures) in schools.