Actually Periyar originally said that Reservation should be only for those who are not belonging to the Kshathriya, Vaishya and Brahmana Groups , since those groups did not suffer due to casteism of the past.
But in TN, the big Communities which are Kshatriyas (Landlords/Soliders/Warriors) and Vaishyas (Traders/Rich Businessmen) are categorised as OBCs.
kerala is no better. P Chidambaram belongs to the wealthy and socially powerful Natukkottai Chettiars and they are personally very wealthy and own textile businesses. But as per reservation rules, P ChiDambaram's grand daughter is a OBC in Kerala and she will enjoy reservation in Kerala. How is it?