Periyar's party and their offshoots worsened the caste seperation more than any other party.... His party was in cahoots with the British during Indian independence. History was corrupted to accomodate him since his party became the prominent party in TN.
I dont think Brahmins physically stopped dalits or others from studying or educating themselves. It was other castes such as Thevars( who are still oppressing Dalits in areas such as Tirunelveli and you can read reports even now) who were perpetrating the maximum atrocities....
But Periyar and all these people did not have the guts to go against Thevars (who were a very powerful and violent community in TN) and others. They chose Brahmins instead since they know they would not fight back much.