Without a shadow of doubt, I agree with the critic's views of Othello never realising the part he played in the disastrous outcome of the play. Ill fate, his mistrust for Desdemona, and Iago's sick, pointless arts definitely did play their parts in the tragedy, but, up until his last words in his final soliloquy, Othello never realised his guilty role.
Othello's biggest flaw was that he let his emotions run the show. He never once reflected and realised this. Instead of being cool, calm and collective in uncomfortable situations or in doubt, which is the way he would've acted in times of war, his inner feelings took total control over him. This got so out of hand that he ultimately turned himself into a cold-blooded murderer.
I am a firm believer of fate and that the stars create inevitable outcomes, some splendid, some tragic. This fate was certainly rubbing against Othello in the play.
It manifested itself throughout the play, bringing about the horrid outcome. One example being when Desdemona dropped the handkerchief in an act of pure good in Act 3/3/290. Ironically, this went against her when Emelia found it and gave it to Iago. Othello then let Iago manipulate him with the handkerchief, which was used as the biggest fake proof of Desdemona being unfaithful. Another instance of fate was the terrible timing of Emelia knocking on the door in the final scene, 5/5/86. Had she arrived a minute earlier, Othello would have been delayed with his sinful act, and may have possibly been put off the act all together with some word from Emelia. But the luck that ran against Othello cannot overshadow the how guilty he is. He never checked up the proofs and ended up trusting Iago over his wife.
The other theme that played a significant part in the outcome of the play was the opportunist, Iago. He took every opportunity to play mind games with Othello, and was let in so easily. Othello showed how pathetic his will power was, and with some tantilising thoughts from Iago, sent himself spiraling into self-destruction. It all started with Iago's comment of "Ha! I like not that." In Act 3/3/34. This planted the seed of doubt in the Moor's mind and set the platform of Iago's ultimate plan to destroy Othello. Iago knew where he wanted to end up, but had no exact route, and Othello's weak mind didn't make it any harder for paths to open up for him. For instance, Iago didn't actually plan for Othello to kill Desdemona, this came as a bonus. In fact, it was Othello who first thought in terms of murder, when in an emotional outburst he cried, "I'll tear her to all pieces!" when referring to Desdemona being unfaithful.
Othello's guilt in the tragedy can be clearly seen by all; yet, in his final soliloquy he completely fails to see it. He blames his jealousy and ultimately the murder on Iago, when he states he was "being wrought"-5/2/347. What he is basically saying there is that Iago killed Desdemona, which is not the case. He smothered her with his evil hands. Iago didn't put a gun to his head and command him to kill her. He then says "Like the base Indian, threw a pearl away"-5/2/349. I fell this gives a big indication of him not understanding how selfish and guilty he was. Othello's saying here that in murdering Desdemona, he threw away his most precious possession. He's not realising that he took someone's daughter, someone's friend and most importantly, someone's life.