Rand Paul makes himself out to be a libertarian. One of his big inspirations is Ayn Rand, a woman who believed that the value of other people is overrated. She believed no one should be forced to pay taxes; taxes are theft in the name of altruism and that only moochers needed handouts. She glorified the major producers, seeing them as the ultimate step, not in need of reliance from anyone. These are the philosophies that Rand Paul and many other Republicans, including Paul Ryan, are embracing right now.
So why is it that a man who believes that no one should be allowed to mooch off of "the producers" voted against a plan that would have effectively killed Medicare? Rand Paul can jazz it up all he wants, saying that he didn't think Ryan's plan went far enough; but that is not why he voted against. The logic is right there in the philosophy that he embraced from Ayn Rand; valuing other people is overrated.
Rand Paul hates it when his taxes go for something that he doesn't use. He is totally against his taxes going to help other people. However, Dr. Paul runs a practice, and many of his patients are on Medicare. His practice makes a lot of money off of charging the government for patients of Medicare. Paul Ryan hates his money going to help other people, but when it's our money going to help him; that's different. Rand Paul is just embracing the philosophies of Ayn Rand to their obvious conclusion; Rand Paul and other Republicans hate it when people have to pay taxes for things, unless those taxes directly benefit them. Then suddenly it isn't socialism, it can't be socialism, because they benefit from it.
This isn't the only example. There are plenty of examples in recent years where Republicans sell out in the name of their own gain. Republicans want to cut government spending and hate government handouts, unless those handouts benefit them. Oil subsidies and financial bailouts for Wall Street go to their biggest supporters; and like any trained dog, Republicans know not to bite the hand that feeds them. They may make a spectacle about being fiscally conservative to their constituents, acting like they are the alpha dogs of the pack; but when it's supper time and all their barking is done with, they know not to bite their master's hand. Rand Paul may posture that he is holding out for a better deal, but the truth is he wouldn't dare cut Medicare; because for all his talk of hating big government, he wouldn't dare bite the big government hand that feeds him.