Rand Paul may have its faults. Many people like libertarianism but they don't like the pro-religion/prolife and pro-rich aspects that come with it. That's why Bill Maher has distanced himself recently from the libertarian appelation.
However to say that it's not sincere coming from Rand Paul is not fair at all. If you know a little bit about who he is, who his father is, you couldn't say that...
Of course Rand Paul is building a political portfolio for 2016. The filibuster, the TSA, the balanced budgets and now this, it's all going into it. But all these political actions are in line with who he is and what he represents.
And still, after all that there's a very big chance he'll lose to a generic republican like Rubio or Ryan in the primaries.