His turn in based on your pictures wasn't wildly different but I havn't studied the replay on that, in any case Olddog is entitled to carry on racing whereas Shaun wasn't, he was toward the end of a long drawn out accident and should have realised - after the considerable time since his accident started, that he was having an accident. Cars where passing him and infact Olddog was, arguably, the second car to go through.
Olddog was still racing and had every right to carry on as normal and expect Shaun not to interfere with his chosen line. A driver rejoining the circuit has no rights at all. It's simple really, he had an off track excursion and turned it in an accident without lifting or ever recovering the car.
Olddog on the other hand was racing, not having an accident, and become involved in the tail end of another drivers accident because that driver rejoined the circuit and not only "didnt look" so to speak, but was pushing hard despite not yet recovering to the racing line.
Personally, and of course it is just a personal opinion, I cannot see any justification for Shaun at all. Whilst it isn't the end of the world and accidents happen, that doesnt make it a "racing accident" just because both drivers where racing. The fact is one of them shouldn't have been at that moment in time.
It's also important to remember that Shaun was technically the lead car at the onset of the incident, and therefor it was Shawn who "closed the door" by restricting the road available to Olddog, and Olddog has established significant overlap - infact he was infront at the point of contact.
Olddog cannot be expected to see sideways and still look where he's going.