Time for some armchair speculation. Since Subramanian Swamy, being an Econ PhD from Harvard and one-time professor there, couldn't possibly be as ignorant about Economics as his letter to the PMO suggests he is, he is most probably being manipulative, in my opinion. If real world politics is as smart as 'House of Cards' and 'The West Wing' would have us believe, then it might be a tactic to elicit even louder public support for Rajan, and make keeping him for another term easier for the government, in the face of opposition from factions of business that the government can't openly defy. But my theory 2 is that the real world is not American television, and that Swamy is a bit of an egomaniac and a little dismayed in his old age that he is not more widely thought of as the Econ genius he is inside his own head, so he takes any opportunity he gets to attack others who are thought of in that way. In the past, he has slandered Amartya Sen as merely a Gandhi family flatterer, and now, it's Raghuram Rajan's turn.