You could just as easily have cited Aristotle or Augustine or Aquinas or any other philosopher who wrote an ethics. The previous commentator didn't invite a utilitarian-type response. He implicitly posed a question about the justification for the ordering of goods in society. Nothing about that statement is definitively answered (or even satisfyingly questioned) by big-U Utilitarianism.
Since you appear to enjoy a little bit of philosophical discussion, let's break down what you ackshually said:
> To answer that question with any degree of rigor one has to go back to the beginning and study the works of Bentham, Mill and others—and the many issues that surround utility and utilitarian principles.
The "beginning" of ethics hardly begins with Bentham or Mill or even the Enlightenment. Utility is quite a modern concept in ethics. The question of what is "the good" is presupposed in any system of value. "The greatest good for the greatest number" is perhaps one of the more perverse interpretations of human good on record.
> This involves such issues as the greatest good for the greatest number, greed overpowering well established moral norms and the fact that the majority of modern states and cities were founded on utilitarian models where a lot of give-and-take was involved before workable consensuses were achieved.
The majority of modern states and cities were most emphatically NOT "founded" on utilitarian models. Most states predate any notion of such post-hoc rationalizations. Cities were largely founded as commercial centers along trade routes or ports, or sometimes intentionally as colonies. States were largely the results of conquest by militarized groups that were certainly NOT utilitarian. Quite the contrary. In the bronze age, they would have simply been warrior bands centered around family/tribal bonds and vassal/suzerainty relationships founded on violence. By the time of the great early empires around the Mediterranean, formal structures of militarism and class privileges won through violence were the organizing forms of society, not "give-and-take" consensus gathering (unless you mean one group giving up the fight and the other either enslaving them or killing them outright).
Maybe you could have argued they are founded on something like Hobbesian social contract theory (certainly not Rousseau's version) but that, too, would suffer from being simply "not true in fact."
The main point that "obvious solutions aren't necessarily the optimal ones" suffers from being trivial, condescending, and a non sequitur. The commenter didn't offer a solution as such, but raised the obvious question of why they should have to pay for someone else's choices. Utilitarianism is the worst of all philosophical answers because it entails the most absurdities.