This section is about incident/accident analysis. I suggest that we stick to the incident.
Coming up with a 5 year old advertisement picture as a means to make other readers form a negative opinion about a dive shop borders on slander and is inappropriate in this section. The usage of the terms divemaster and instructor shows that the writer did not have knowledge of the terminology of the diveworld. Changing news articles afterwards would be the same as witnesses changing their stories, in a subjective way after gaining knowledge.
As for the circumstances, divers who are interested in taking the divemaster course, have to make fundives until they reach 40 logged dives. None of them will be actively assisting during a course. The initial reports about divemaster trainees was probably due to a lack of knowledge, just as this was illustrated by the use of the words divemaster and instructor.
The OP mentions the use of a flag. Nobody uses a dive flag in/on the water, just a SMB when surfacing. Flags are used on the boats. If a SMB was meant, don't use the word flag. Incorrect use of terminology leads to confusion.
The unfortunate lady was killed by a boat propellor. I've been on lots of smaller boats which are used to get from the beach to the diveboats, which are out on the 2nd reef. Everytime there was 1 person sitting on the bow, checking for bubbles in the water. If any bubbles were present, the captain was signaled so he could slow down and check which way was the safest to avoid divers. Not a single word in the articles about this.
Yes, divers can get separated in a class. One student dives in a wrong direction, while the others keep going. It's a situation that requires an instructor to get his group back together. And this time, while he was attending such a diver, the other two students ascended, one of them ending up in a boat propeller. It's an accident. Not homicide. Can the instructor be blamed for this? Yes, he should have used another approach, e.g. use his divemaster. His negligence was so severe, that his license was revoked.
What else is there to learn from this accident?
Keep your class together, having a divemaster to assist is better.
If you're taking a boat over a divesite, have a lookout on the bow.
And that's it. Lawsuits, blame games and slander are not for this section.
P.S. please learn the difference between their and there. Thier is not even an English word.