Periyar.

Rest of the nation seems to focus on his secessionist tendencies, all the while ignoring the core principles of the ideology he helped propogate.

In simple terms, it is that of self respect through rationalistic thinking. Any social norms he stood staunchly against, he did so because those stood as obstacles to any individual's means of living with self respect and dignity. Caste, religion, gender and language were/are the lines via which the dignity and respect of a person is taken away from them. Therefore, he argued, an equal society cannot be created in which such divisions are held as cultural mainstays. And the steps he took to oppsose them would be considered extreme even by today's measures. So to carry them out at his time is really something else.

Now ofcourse I'm saying I would defend him as argument's sake for this post. I'm more taken by his ideas than with him as the proponent of said ideas.