In the first paragraph of the Libertarianism section Merry questions the possibility of Christian libertarianism. Hmmm. Merry is apparently unfamiliar with Lew Rockwell and Gary North and Thomas Woods.
In the second paragraph Merry argues that Engelhardt's use of biblical references to defend some of his libertarian views is inappropriate. As an atheist, I frankly do not think anyone should cite the Bible as evidence for anything. Because I am not a biblical scholar, however, I have no comment on the merits of Merry's discussion.
In the third paragraph Merry criticizes some of Engelhardt's libertarian views from a utilitarian standpoint. Merry's views are the opposite of reality (e.g., libertarianism is the best economic policy for the poor). In addition, the proper basis for libertarianism is the rational natural-rights ethic (self-ownership and original appropriation and non-aggression) promulgated by the LIBERTARIAN BIOETHICS BLOG, not utilitarianism.
In the fourth paragraph Merry attacks Engelhardt's libertarianism via a positive rights approach (freedom from want). Merry is apparently unaware that positive rights are illegitimate and, sadly, he is specifically horrified that libertarianism demands that "all social programs have to be premised on the consent of each and every individual person." Once again I am fascinated by the fact that non-libertarian bioethicists commonly support "patient" autonomy but not "citizen" autonomy.
In the final paragraph Merry finally lands a blow when he queries why "Engelhardt does not believe that transactions - in the form of gifts or bequests - can be compelled by the state" but simultaneously seems "unperturbed about other paternalistic, 'coercive' actions of the State that interfere with individual liberties (e.g., compulsory schooling, scientific research, the building of libraries, roads, parks, defense, emergency relief aid)?" This the classic libertarian anarchist argument detailing the philosophical incoherence of minarchism. Bravo, Mr. Merry! However, Mr. Merry, the appropriate solution to Engelhardt's problem is not to adopt democratic socialism, as you suggest; rather, Engelhardt should abandon minarchism and immediately adopt libertarian anarchism, the philosophy promulgated by the LIBERTARIAN BIOETHICS BLOG.