For new players the 3.0 trailer is meant to entice them for them to go, oh this person dies, they look into it and go oh wow she is the leader of a nation, and then if they ask friends they will learn that the person being depicted, the hyuran is a representation of our player and how they are being blamed. They will be intrigued and want to see how this chain of events occurred so for new players they wouldn't be "spoiled" because it's meant to entice them to want to see how things turned out this way.
As for players who have been playing as mentioned countless times they warned players not to watch it if they haven't completed the 2.55 story yet because those are the players who have been following the story which would not want to be spoiled.
Basically the Trailer isn't spoiling new players it's enticing them, to get them interested in the game, to want to learn how those events came to be.
