Literary Criticism is theory dense and uses jargon that is difficult for younger or less trained readers to understand. It is our job as teachers to find ways to make these intellectual tools more transparent and useful, both to younger students and to the general public.
We all operate under layers of implicit biases, and it is very important to civil society that we are able to bring our unexamined biases to consciousness and to realize that our biases have a profound and rippling effect on those around us. If we are in positions of power, or relative power, our unexamined bias can harm others without our awareness of doing so.
You write: The student may be there with one mission: “Teach me about the history of the Civil War,” however even a preschool student can discuss an event from different viewpoints and come to appreciate, for example, that an argument among friends is seen differently by each person involved. That is the root of Literary Criticism, and certainly a topic as complex as the history of the civil war needs to use this tool to make studying the subject worthwhile.
I do not disagree that the structure of academics can produce endless self-referential loops. The patrimony of mentorship often creates a closed system, which can undermine the inflow of new and useful ideas.
More to the point, only a handful of higher academic institutions require professors to engage in the art of teaching. I would say that undergraduate teaching suffers most from a lack of teaching skill or introspection on the part of professors and grad students about the role of a teacher, the skill set a teacher needs to make their teaching useful to those new to the field and most of all to teach students that an honest awareness of ones own biases is an ever deepening and never finished process. Literary Criticism does offer us the tools to engage in this process and the language to reveal bias (or perspective) to others.