What absolute non-sense! There is no such religion called Hinduism. An average Hindu Punjabi has more in common with an average Muslim Pakistani (Language, Food, Music, etc.) than a Hindu Tamilian. But the Punjabi/Rajasthani and Tamilian or both clubbed into a single Hindu religion.
A Tamilian sacrifices Goat to his God. But this is not accepted by the Brahminic Hinduism as a way of worship in their temples. But all of these are merged into a false identity of "Hindu".
Who is a hindu according to Indian law ? One who is not Muslim or Christian or Jain. Because there is nothing else that commonly unites them. Hindu is a western term for the land beyond Indus and it is not a religion for all these years (until the politicians decided to use it to suit their purposes). Saivam, Vaishnavism, etc. were the original religions of this land. Not this abomination called Hindutva.