I believe that this student's conclusion is correct, but I find it absolutely astounding that she does not cite Plenty of Blame to Go Around or any of the other published treatments of the ride. Frankly, I think that there may have been some plagiarism here, but I cannot prove it.
Despite that, her analysis is right on the money.
I think she's right about Stuart, but I think she's wrong about Lee.
I think the persons to blame for the ANV's loss at Gettysburg are primarily the men who wore the blue that day. I think Lee overall did a creditable job. His decisions were reasonable given what he knew at the time he made those decisions. He was overconfident to an extent, but he had reason to be very confident in what his men could do. He underestimated what the Army of the Potomac could do, but he had reason to do so.
She writes that Lee planned to strike the center of the Union line on the night of July 2, when clearly his plan was to attack in the same manner as had been done on July 2, along the Emmitsburg Road, and that plan had to be abandoned on the morning of July 3, as Pickett's Division wasn't in place. I don't think she gets the meeting between Lee and Stuart correct.
I think she's right not to fall into the Carhart trap of believing Stuart was to be part of the attack on the Union center on July 3. She's right that he was to protect the left flank. That's the explanation that makes his firing the cannon make sense. He wanted to see if any Federals were around that area.
I think she's not critical enough of Robertson, and I think Stuart bears some responsibility for leaving Robertson in charge and not placing a more competent officer in charge of that mission.
But overall, in the case of Gettysburg, I believe the Federals won that battle more than the confederates lost it. Officers like George S. Greene, Winfield Scott Hancock, Gouverner Warren, Strong Vincent, O. O. Howard, Patrick O'Rorke, and that professor from Maine made crucial decisions at the right time, and the soldiers of the Army of the Potomac, who were always good soldiers and always fought bravely and gallantly, did the rest.
In the words of Scott Hartwig, the Army of the Potomac was an army of lions that had been led by jackasses, and at Gettysburg there were a lot fewer jackasses.