The most contentious issue involves the origins of Hinduism. The common historical view, included in all textbooks, is that Indo-Europeans from Central Asia, called Aryans, migrated to India and laid the faith's foundation. But Bajpai and the Hindu groups hotly dispute the idea of any Aryan migration, citing new DNA evidence for their view that Hinduism developed indigenously. They have asked that textbooks include both views.There is of course no new DNA evidence that Hinduism developed indigenously. The latest studies suggest that Indians are of largely indigenous origin, but that does not mean that their religion is. Hinduism is a blend of many elements, and the contribution of local elements in it should be acknowledged and celebrated, but the binding thread is the religion of the Vedic Indo-Aryans, Sanskrit, and the Brahmin caste.
The latest research actually reinforces the Aryan Invasion Theory. According to that theory, the caste system is not a simple "division of labor" as the revisionists would suggest, but rather a social structure imposed by an intrusive group. A prediction of that theory is that the upper caste in the Hindu system would carry a greater genetic legacy of non-South Asian ancestry. This prediction is supported by current evidence.
The indigenist school must explain why Brahmins are more "West Eurasian" genetically, if they were just assigned this role in a grand within-India "division of labor". A more parsimonious explanation is that they are more "West Eurasian" genetically because, well, their ancestors came from West Eurasia.
Moreover, the "division of labor" theory could accommodate exogenous origins for some Indian castes, but it does not explain why the elite group also happens to coincide with the exogenous group, namely the Brahmin caste. A more parsimonious explanationis that the elite group is also the exogenous group, because a group of outsiders took control of Indian society and placed themselves on top.