Lacking Backstory

Reading through Act 1 of Othello for the first time left me with a number of questions about the characters' relationships with each other. Iago clearly views Othello with disdain despite being forced to serve under him by the rules of the military. He describes his struggle between his personal feelings and his duty saying, "Why, there's no remedy. 'Tis the curse of service; preferment goes by letter and affection, and not by old graduation, where each second stood heir to th'first. Now, sir be judge yourself whether I in any just term am affined to love the Moor" (page 556-557 lines 34-37). He then shows his dedication to order and the laws established by telling Brabantio about his daughter's betrayal. This method allows Brabantio to legally make charges at Othello, which he does. Were Iago not such a lawful character, he could have simply attacked Othello or confronted him publicly. This was an effective introduction to the story if the other acts focus around Iago as the main character. If it turns out to be Othello, which makes sense because of the name of the story, it seems like an odd place to begin. However, in lines 128 to 169 Othello explains how he met Desdemona and the beginnings of their relationship in order to fill in for that missing backstory. If it were a normal story this would not do it justice, but it works given that it is a play pressed and therefore pressed for time.

I enjoyed the story so far because it hints at an interesting controversy with an impending tragic fall, but I feel that several things didn't add up. Why would a father who just discovered his daughter is married be so easily calmed down by the secret husband? How does Othello not notice that Iago hates him and proceed to leave his wife in Iago's care? Will there ever be a rational explanation for Iago's deepseated hate that may lead readers to side with his actions? Why were the military leaders so willing to listen to a petty issue when they are busy preparing for an invasion of Turks?