What should be our defining moral principle here? Utilitarianism? Moral relativism? Marx? What should be our guidance?
None of those seem to work as a moral guidance for the collective good because nobody knows what the heck is good for the whole. Utilitarianism is not a moral principle; in fact it needs a moral principle to be utilized. A moral principle of which utilitarians to this day are never able to agree upon, nor justify to the rest of us.
Moral relativism is completely individualistic, and cannot guide a community without the authoritarian rule of an individual with complete disregard to the demands of the people. If we are looking for a collective aim for the common evil, look towards moral relativism for guidance.
I don't know if Marx was a moral philosopher or is considered a moral authority. You could go with Kant, but his moral system was held by the free will of the people, making an authoritarian involuntary collective an entity unable to conduct moral decision. He was also a liberal, understanding the importance of the liberty of the individual.
In the end the good of the people is understood individually. You can tax somebody as much as you want, but doing such doesn't convince such people the values of giving to the community. You could be an individual and love the community by contributing to it, which actually teaches the community a moral alternative, or you could be a collective authoritarian and love your neighbor by taxing another neighbor. How inspirational.