Persepolis.

Why did Marjane Satrapi choose to write negatively about the United States through the negative opinions the Iranians shared?

Why did the author choose to end the story in a very depressing, no-hope ending?  There was no resolution for the reader at all.

The book was written in a style following a young girl, yet that style also reflected extremely important political information on Iran internally and externally.  Was all the information exactly accurate and unbiased in the novel?  Or did it have a particular stance?