I can understand Delta wanting to manage the communication and information on this incident. I have worked in corporate communications and crisis management, etc. I requested that Delta provide me and all other passengers with some sort of follow up report as to what happened during this flight. I did not ask for an immediate report. Delta did an admirable job with their initial communication to me (presumably to all passengers) acknowledging the uncomfortable flight and crediting us with 15K Skymiles as compensation. This email was sent out to me within 4-5 hrs. after the flight. I can also understand the concerns of a potential lawsuit. Of course, a lawsuit would only have merit if Delta did something wrong.
Many years ago I pursued my private pilots license, but have not piloted anything bigger than a 172, so I wouldn't presume to have any knowledge or experience comparable to many of you here. All that I do know is that the flight was totally uneventful and smooth until the pilot made an abrupt warning to passengers and cabin crew to sit down and buckle up. The turbulence we encountered after that would clearly be deemed severe. The plane 'dropped' several times and then slammed into something. The food and beverage carts were knocked over. At least two (from what I could see) overhead bins popped opened and luggage came out. The captain (presumably) came on and said he was having trouble with the Chines ATC in getting around the weather. The cabin crew did a good job at checking on everyone afterwards, restowing luggage, and distributing extra air sickness bags.
After deplaning in ICN, many passengers stopped outside the jetbridge to take pictures of the aircraft damage. I took some pictures as well, and a pilot emerged from behind me from the jetbridge. He stopped when he saw the aircraft and stared for a few seconds, then took his phone out and started snapping some pictures as well. Some of the other passengers came up to him and asked if he was flying the plane. He said no, he had been in the crew rest area when the turbulence hit... and he said all he could do was hold on while he got knocked around.
I had to run to catch my connecting flight onward to MNL. Upon landing in MNL I checked my emails and Delta had sent their customer care email. Subsequently, I have only asked that Delta provide us with some additional follow up to the flight. Their final email to me was that they would not be responding to any more of my inquiries, would provide no more information, nor any more compensation. I had never asked for any more compensation, only for information. According to the news reports, Delta told the NTSB that there were no injuries nor any significant damage to the aircraft, thus no investigation would be conducted.