From libertarian Michael A. LaFerrara:
Rights are moral principles sanctioning every individual’s freedom of self-advancing action, not an automatic claim on material benefits that others must be forced to provide. Healthcare does not just happen in nature. It must be produced by the individual efforts of human beings, and that fact of nature cannot be arbitrarily wished away. For a government to guarantee a right to healthcare beyond what one can acquire through voluntary dealings with others, the government must force others to pay for and/or provide it. To do that, the government must have the power to commandeer the efforts and property of productive citizens: i.e., the government must enslave those citizens.
“Unconstrained capitalism” is an interesting package deal, since capitalism is the only social system that banishes aggressive force from human society by constraining the government to the task of protecting every individual’s inalienable rights to life, liberty, and pursuit of happiness, which necessarily includes the right to the product of one’s own, not others’, work. Once we accept the notion of a right to healthcare or any other material benefit that others must be forced to provide, we have abandoned the basic principle of capitalism—a society in which each person is free only to deal with others by voluntary, mutual consent. Then we’re left with the basic principle of socialism, the society of masters and slaves, in which material need makes one a master and the ability to satisfy that need makes one a slave—“from each according to his ability, to each according to his need,” with the government as the tool of the masters rather than the institution to secure equal rights.