There are facts and imaginings, the latter spawns tourism, media and forum topics. If imaginings are eliminated and only the facts remain, they are the " how", not the "why".
The best we can do is employ a legal model to see what fits. This is means, motive, opportunity. This is circumstantial, eyewitness and physical evidence.
By what means did events transpire?
What was their decision making processes?
What opportunities were present?
What circumstances contributed to their demise?
Who saw anything?
What material objects explain the outcome?
In a court of law, a verdict can be achieved on incomplete evidence. In the court of opinion in the forum, the same is true. Although attorney's are distrustful of eyewitness testimony, it is the closest path to answering the "why." Question. We do not have it...yet.
For the most part, addressing the tragedy is akin to a game. The reward is not so much winning as it is how well one plays the game. Some feel they win because they are analytically minded, others intuitive. We use their 1959 misfortune to better understand ourselves.