Why did edgar allen poe assume the name allen as his middle name

The setting.

Explanation:

In the given excerpt of "The Spirit of Alcatraz", the author begins by telling about the 'historical' fact of the infamous nature of the word "Alcatraz" and how it immediately reminded people of the infamous prison in the place.

Alcatraz used to be a maximum security prison for imprisoning notorious and dangerous criminals. But even after the prison was retired from operations, the prison's presence stuck with the name. It is this legend that the writer is talking about in the given passage.

Then the author presents a conflict in the narrative when he presents a different perspective for the American Indians. For them, the place meant "a symbol of freedom", which is in direct conflict with what the other people generally associate with the place.

This differing perspective about the island gave a conflicting aspect of what the place holds for the people. But the overall purpose of the narrative is to give the setting of the text.