I believe that Coleridge would like to believe that the mariner is a universal figure that transcends all limits of culture and geography. As a movement, the Romantic thinkers were convinced that their convictions were universal elements that could be applied to any situation. They did not see themselves limited by culture or geography. They did not see the meaning of their work as limited by such contexts. Certainly, Coleridge believes that about his mariner, who operates in a symbolic capacity to represent all humanity.
The idea that the mariner is a universal figure who transcends culture or geography is seen in the themes of the poem. Consider that the lessons the Mariner learns are ones that are universal. There are no contexts that limit the learning of the mariner. The mariner is a symbolic representation of human beings and the lessons they must learn as a part of maturation. He learns that the cost of a rash act of destruction can carry with it profound implications that are almost beyond the realm of human calculation. The mariner learns of the value of life as intrinsic. Consider the closing words that the mariner lives by in his own life:
He prayeth best, who loveth best/ All things both great and small;/ For the dear God who loveth us,/ He made and loveth all.
Coleridge's words to this point are not limited by any cultural or geographical constraints. In the use of "all things" and the invocation of God as a life force, Coleridge wishes to make the narrative a universal one. The lessons that the mariner learns as well as his own maturation to understand such lessons are universal. The "sadder and wiser man" that emerges from such life lessons and truths is a universally symbolic one. Coleridge is true to Romanticism in his idea that what is experienced has universal application regardless of culture or geography.