Exaggerate much? If Brees could complete a deep corner route against zone coverage 95 percent of the time, he'd never lose a game.
And you're completely wrong about what happened on that play. Maybe the defensive backs you faced in high school would have made it an easy touchdown, but nothing you said actually happened on that play. Frazier was cheating toward the outside as he dropped back after the snap, and Awuzie had his hips turned and was running deep under Sheppard's route before Manning even cocked his arm to throw. The tight end was open in the flat under Awuzie, but with 46 seconds left in a two-score game, that's where you WANT Manning to throw the ball. If Manning had tried to hit Sheppard, it's very likely Awuzie at least defends the pass if he doesn't pick it off, and Frazier easily could have gotten to Sheppard before he reached the end zone -- if Manning had made a perfect pass and Sheppard had somehow caught the ball.
Speaking of exaggeration, how about your generalization of a specific play? Brees makes that throw facing that coverage all day long.
Do you have a different video of the play? Apparently we're not seeing the same thing.
When OBJ starts his move on about the 25 yard line, Sheppard's at about the 27 running and Ellis is starting his cut at around the 35. Frazier's at the 10 backpedaling and Awuzie is at the 25 side-pedaling. Keep in mind, at this point, Sheppard is running forward while Awuzie is side-pedaling and not committed either to him or Ellis.
When OBJ is at about the 12 is when Manning lets go of the ball. At that point, Frazier is at the about the 7 (5 yards away) directly in front of him still backpedaling and Shepard is at about the 17 (10 yards away) and moving to his right. Awuzie and Ellis are not in the frame. Manning threw the ball to the middle of the field and Frazier never did catch up to a guy who started closer to him by 5 yards than Sheppard when Manning released the ball.
So what makes you think that 1) Manning can't throw Sheppard open away from Frazier (especially if he flinches or pumps to the post) when he threw Beckham open away from Frazier when Frazier was 5 yards closer to Beckham or 2) A guy who was side pedaling when we last saw him and is not close enough to be in the frame is going to recover and defend Sheppard who was running forward .....especially when Manning demonstrated on the same play he can throw guys open. Unless Manning under-throws the ball or puts too much air under it, he can put that ball out in front of Sheppard's inside shoulder or straight over his head and let him run under it.