Responsibility or Authority?

The articles for this reading all discuss, in essence, what responsibility, if any, writers have to the characters they portray. There is discussion of truth, and whether the writer or the character possesses the "truth", and determines the truth. Barbara Smith argues that regardless of what one writes, someone will always find some way of disagreeing with it, and thus writers should simply seek to write their truth, regardless of what others think of it. Others have argued that an improper treatment of a character, particularly of a certain social class, reinforces harmful stereotypes, and thus should be treated with caution.
All of these arguments seem to imply some element of truth, where, ultimately, there is no way to definitively determine the truth. Leaving existential philosophy aside, there is simply no objective litmus test for truth in regards to social structures. Science and mathematics possess "truth" in the form of facts, and debate over whether or not they exist is effectively irrelevant on a universal level. Many did not believe that gravity affected objects of different weight in essentially the same way, but that did not mean that gravity decided to bend to public opinion, and alter the laws of physics to fit what was "socially accepted" for that time period.
As society is constructed by humans, it is subject to whatever humans wish to accept as part of its "truth". The question then is, who ultimately gets to determine this concept? It is fair to say that no one can be considered completely unbiased in this respect. Thus perfect objectivity would only be achievable through universal consensus on a certain topic,  of which there will never be, or by someone being elevated to a sort of omniscient being. As neither is practical, as far as we know, the answer must fall into some element of responsibility, as some writers describe it. That authors have a certain responsibility to depict certain people in certain ways so as to not incite community or societal tensions, and in fact should use such an opportunity to promote a lessening of these tensions.
But the problem here, and the problem which many of the proponents discussed in these readings face, is a lack of inherent authority. While one might be able to argue for a responsibility for society, no one has any kind of inherent claim as to determining what is responsible and what isn't. Many of the authors claim to have made this determination, but none of them prove why we should believe them at all. There are no elections for who speaks for such matters; it's simply a matter of convincing enough people that one is acting in their best interests. The compromise to this is the multitude of writers adding to the "national conversation", which, when examined is less "conversational" and more "pontificational".
The problem that all of these writers face in this argument is that none of them can make a claim as to why they have the authority to make decrees on this issue that will prove compelling enough to enough people to make enough of a difference. Ultimately appeals to common reasoning a logic are the only true recourse, which will generally lead to some popular consensus, but even then, as long as there is dissent, there will be no evidence that this consensus is the "truth".