Othello is considered to be a one of Shakespeare's great tragedies although it differs in style from others such as Hamlet and Macbeth because it concerns a more personal level- Othello's wife, Desdemona, rather than a broader level like Macbeth where a whole country (Scotland) is affected.
In determining the final judgment of Othello himself, his trust in "honest" Iago and his passionate personality must be considered. The influence Iago has over him is indisputable and is one of the factors that makes the audience, as they watch him destroy himself, feel compassion for Macbeth, who "loved not wisely but too well" (V.ii) .
Othello seems confident in having won over Desdemona - "she had eyes and chose me" (III.iii) - but his insecurities and the fact that he is, in his own estimation,ultimately nothing more than, a "turban'd Turk," do contribute to him being easily manipulated by Iago. Othello holds reputation highly and justifies his actions because "nought I did in hate, but all in honor" (V.ii)
Othello does refuse to believe Iago's claims of Desdemona's infidelity without "ocular proof" and when he gets it, despite having second thoughts "...thou dost almost persuade/ Justice to break her sword"(V.ii), he concludes that "so sweet was ne'er so fatal" and she must die, even to save her from herself. Othello feels responsible and " I can again thy former light restore."
Hence the audience or reader does recognize the overwhelming confusion that Othello feels. He cannot believe an honorable soldier such as Iago would lie to him - and for what purpose- so is unable to rationalize and to judge Othello would be harsh. he is a victim of his own circumstances, a tragic hero!