Rights based moral theory?

Mackie claims that "in general, people do not and cannot make an overall choice of a total plan of life" (pg 175). Moreover, "there cannot be an acceptable moral theory that is not right-based". (pg 176). From these two premises Mackie contends that the fundamental right in which other rights are based off of is the right of "persons progressively to choose how they shall live" (pg 176). Ideally this right does not sound that bad. However, after speculation one realizes that a person's choice of how to live interferes with the choices of others. In theory, to combat this problem Mackie offers up a version of an inverse square law saying, "a right decreases in weight with the remoteness of the matter on which it bears from the person whose right it is" (pg 177). Again, when trying to apply this things can get messy. Mackie even acknowledges in the postscript that "we may have to tell a busybody that something is not as vital to him, from the point of view of his moral theory, as he thinks it is" (pg 181). Nevertheless, Mackie has many questions left unanswered about the implications of his theory. To combat these Mackie simply states that "what I have offered is not an algorithm or decision procedure, but only, as I said, a model, an indication of a framework of ideas within which the discussion of actual specific issues might go on" (pg179). Lastly, what I found interesting was a distinction that Mackie made at the end of the reading regarding moral theory saying "it does not seem to me to be a reasonable requirement for a moral theory that it should, even when fully developed, be able to resolve all conflicts" (pg 181). I think in class we really have not considered this a possibility, that a moral theory is not required to resolve all conflicts. It seemed to me that we were looking for a perfect theory. Mackie contends that this is not necessary. I understand how this can help in terms of applying a theory, but should we be so laid back about judging our moral theories?