Othello Act 1 Scenes 1 and 2

Reading the first two scenes of Act 1 of Othello has given me a pretty good generalization of the characters and I think I have an idea about what is happening in the story so far. Roderigo is a guy who obviously hates Othello since he says, "Thou told'st me thou didst hold him in thy hate" (I.i.5-6) to Iago. I assume the "him" Roderigo is referring to is Othello because he is the main character. Iago assures Roderigo by saying, "Despise me if I do not." (I.i.7-8). Roderigo also displays his hate for Othello by saying, "By heaven, I rather would have been his hangman." (I.i.81-82). Roderigo makes a racial remark about Othello when he calls him "the thick lips". This refers to Othello's African heritage. Iago and Roderigo then walk by the house of Brabantio and yell to get his attention, asking if he's been robbed. When Brabantio comes to the window Roderigo flat out tells him that his daughter is having sexual relations with Othello: "I am one, sir, that comes to tell you your daughter and the Moor are making the beast with two backs." (I.i. 113-114). At first Brabantio is in denial and calls Roderigo a liar but Roderigo tells him that he speaks the truth and Brabantio admits he had a feeling this was happening: "This accident is not unlike my dream. Belief of it oppresses me already." (I.i.139-140).
First of all Roderigo must really be out to get Othello if he tells the girl's father that she is sleeping with the Moor. There's also some jealousy behind Roderigo's scheme. He must be angered by the fact that a rich man such as himself can't get the girl but a black man can.
Second of all Brabantio must be really oblivious to what his daughter is doing when he's not around. He even denies that his daughter would do such a thing, which suggests that he and his daughter don't have a very good relationship. Brabantio is surprised that his own daughter would go behind his back like that: "How didst thou know 'twas she? -O she deceives me." (I.i.162). He didn't even know she and Othello were married. Brabantio even questions his own parenting by saying, "Fathers, from hence trust not your daughter's minds by what you see them act." (I.i.167-168).
In Scene 2 Iago arrives to tell Othello that Brabantio wants to arrest him. Othello seems to be calm and not worried at all: "Let him do his spite. My services which I have done the Signiory shall out-tongue his complaints." (I.ii.17-18), and "Not I. I must be found. My parts, my title, and my perfect soul shall manifest me rightly." (I.ii.30). Iago seems like he is betraying Roderigo by warning Othello about Brabantio coming to arrest him.
A lot has happened in the first two scenes of Othello. Roderigo hates Othello and wants to ruin his life, Brabantio is on a mission to arrest Othello for marrying his daughter and Othello just wants to live a happy life with his wife. I don't understand why everyone is hating Othello, but I'm sure I'll find out why later on.