Unlike the other women in the book, Emilia understands men and their thinking; therefore she shows no shame for standing up for what she believes in.
It roots into love, deception and jealousy. Shakespeare makes Iago a puppeteer in a sense so that he may control those around him without getting caught, up until his own demise.
The play that was created revolved around the tragic hero, Othello, whose tragic flaw transformed him from a nobleman, into a destructive creature, which would inevitably bring him to his downfall Othello ascends to the rank of the Venetian military, a city - much like Elizabethan England when the play was written - rife with racism.
Both Hamlet and Othello do terrible things, so why do we not think that they are evil characters?
The dominance of jealousy as the chief causative force of action in the drama is very obvious to most critics. By Othello believing the lies, it surfaces his inability to trust and have faith in his own wife. Iago uses both Cassio and Othello to his advantage, noticing how trustworthy they are of him.