He uses racial slurs towards Othello, such as “These Moors are changeable in their wills”, which played with typical ideas of the time that people of colour were indecisive. In addition, he talks about the marriage between Othello and Desdemona by saying “a frail vow betwixt an erring barbarian and a supersubtle Venetian”. When he uses words like erring, he is suggesting Othello is a dysregulated person. He also calls him a barbarian, suggesting he is uncultured and lesser. In Ancient Rome, the barbarians were described as brutes that were constantly fighting. If Iago respected Othello and saw him as an equal, then he would not refer to him as a barbarian. Furthermore, when Iago first warns Brabantio, he again describes Othello in a disgusting way. Comparing an old black ram to a white ewe is the same as comparing dirt to snow. When Iago describes Othello ‘tupping’ Desdemona, he is suggesting that when they are having sex together, Othello is making her dirty, similar to when you mix snow and dirt, creating a muddy mess. A white ewe signifies a sort of pure innocence, and when Iago calls Othello a black ram, he degrades Othello to the title of a beast or an animal. Iago is basically indicating Othello is a black animal out to steal Desdemona’s innocence.
Iago may be commenting on Othello's marriage since he is insecure about his own marriage. Shakespeare hints throughout Othello that Iago has deep and profound love for Desdemona, even though, ironically, he hates her as well. Jealousy of someone an individual loves is the worst jealousy of all, which is why his love eventually shifts into hatred. Iago mentions that he is attracted to Desdemona himself, saying “I do love her too”. He may be insecure that she chose to marry Othello rather than himself.
This perhaps opposes Coleridge's comment “The motive-hunting of motiveless malignity". This suggests Iago has no real reason for acting the way he does. Arguably, Iago's insecurities and jealousy is reason for his evilness. First, Iago is a racist and does not approve of the fact that Othello is a Moor, highlighting his irrational tendencies. Subsequently, Iago is jealous and believes Cassio was rewarded with the promotion Iago deserved, adding anger to his hatefulness. He also subtly tells the audience how he is envious of –and angered by –Othello’s marriage to Desdemona, which may be caused by his disgust by interracial relationships. Finally, Iago is afraid that Othello has had intimate relations with his own wife, Emilia.