If one accepts the Aryan Invasion Theory -- which states that tribes invading from Persia displaced the original inhabitants of the Indus Valley whoo moved into southern India -- there is evidence showing that Siva was worshipped by the inhabitants of the Indus Valley.
The invading Aryans did not have Shiva as one of their gods. Instead they absorbed Shiva into their god Rudra.
Shiva is woshipped throughout Tamil Nadu. Thus, the so-called Dravidian Religion is nothing but worship of Shiva and his sons Ganesha and Murugan (Karthik).
It is clear that nobody imposed Hinduism on the Tamilians. Instead, the Dravidian Religion was made part of Hinduism and even spread among the invading Aryans as witness the temple to Shiva (Vishwanath) in Varanasi and other places.
There are other religions that were imposed on the Dravidians by offers of monetary benefits or by force; e.g., Christianity and Islam. But nobody talks about Christianity or Islam being religions alien to the Dravidians.
Why not?
Te real trouble with Tamilians is that they have a serious inferiority complex. This was fed by Periyar, Annadorai and their followers and still continues under Karunanidhi. That is why you get posts from Tamilians about "Dravidian Religion". These guys don't have a clue about Indian history.
