I think Fitz is getting a bit too much heat on this - that is Gailey's call. He manages personnel and play calling.
That said, Fitz made the decision to go to Graham. Stevie had steps on his DB running into the endzone, CJ was wide open underneath, and TJ had only 1 catch the entire game and has sometimes struggled with holding on to the ball in key situations.
28 seconds, throw underneath to CJ, get to the 5 yard line, then spike it. Chan designs some beautiful plays on goal-to-gos, so use them.
Plus CJ would've gotten the ball, what, at the 11 yard line? He's averaging 7 yards per touch, and certainly would be the most likely to waltz it in. If you're going for the endzone, has to be Stevie. His safety is playing in, and his CB bites up on CJ's in route.
Wrong risk at the wrong time.