In "A Very Old Man with Enormous Wings", how is there a theme of isolation?

There is a theme of isolation in "A Very Old Man with Enormous Wings." Since no one knows exactly what or who "that nightmare" is after he appears at the home of Pelayo and Elisenda, the old man, "impeded by his enormous wings," becomes isolated as an oddity. He then later becomes a mere inconvenience. 
At first, Pelayo and Elisenda overcome their surprise, and they "find him familiar." However, when they speak to him, he answers in "an incomprehensible dialect with a strong sailor's voice." They then conclude that the winged old man is a castaway from a foreign ship that has been wrecked in a storm. However, when onlookers arrive, numerous conjectures are made about this winged man. The priest, Father Gonzaga, promises to write to the Supreme Pontiff for the final decision on the determination of the old man's identity. However, others interpret his identity in their own ways.
Not long after the old man's appearance, other oddities come to Pelayo's home; it becomes a virtual circus. This demonstrates that the irrational is a real part of life and that it should be accepted as such without futile attempts to assign definitive limits to what is in the world. Moreover, by trying to define the old man with enormous wings, people have stripped him of his fantastic elements that are inexplicable but real.