Personally, I tend to disagree with both sides of the argument. I do not think that arguments are bound to races ("Aryan" and "Dravidian" or "Aboriginal"). Ideas tend to travel faster than people and in this sense it makes (in my opinion) hardly any sense to speak of a "Dravidian" argument.
However, I could not resist writing about it after having read a statement about it by V. Varadachari in his Āgamas and South Indian Vaiṣṇavism. I do not know well Varadachari's work, but I tend to have a positive opinion of it. Anyway, here is the statement:
Suggestions have been made by some writers that the Āgamas are antivedic and should have arisen under the impact of the ways of life of the aborigines of India. It is to be observed here that borrowing, whether, linguistic, religious or cultural, is always from those who are spiritually and morally superior or politically dominant in power: minor impacts could have been there on the cultured class coming from the tribes but wholesale concept of the Āgama way of worship could not have emanated from the tribes: the Āgamas must therefore be treated as supplementary to the Vedas (vi-vii).
I understand Varadachari's agenda and his dissatisfaction with the opponents' argument. But I think he should have rather asked "What does anti-vedic mean?" instead of throwing himself into hot water. In fact, an opponent may easily reply that the non-Aryan aborigenals were the large majority of the population in South India and that they could hence easily influence the general culture through their religious beliefs and habits. A parallel could be that of a linguistic substratum. Hence, the conclusion might be true, but the second premiss (the non-Aryans were a minority) does not hold.