No, it’s not a utilitarian approach. A utilitarian approach would be the one you favor: apply libertarian principles to the facts at hand, law be damned. As Justice James Iredell noted in Calder v. Bull (1798), however, no two men agree what the natural law is, and so saying that federal judges are free to apply their own ideas of the Good, theTrue, and the Beautiful means that we’re in a lawless society: one in which the judges can impose whatever policies they want to impose upon us, and we can’t do anything. In short, your solution is akin to that in today’s Iran, where the mullahs make the final decision, or Egypt, where the army does. Unfortunately, a high proportion of federal judges today behave as you seem to prefer, with the notable qualification that they are not libertarians.
When someone becomes a federal judge, he takes an oath to uphold the Constitution. In case he finds this inconsistent with his ideals to such a degree that he cannot in good conscience apply the Constitution, he should resign his office, not enforce principles that violate his oath.