The Event
Problem #1 - Victims
I don't care about them. None of the civilians have been fleshed out, so they're a faceless group like any other. It's the rule of statistics; the further away somebody is from a violent event, the less they care. And, to me, these people are no closer than somebody in Australia, which means it's the ST's job to flesh them out.
A guy stands up in the La Famiglia ball; he's a little buzzed and a little goofy, as he makes a speech about how grateful he and his family are to Sword for protecting his family, and La Famiglia for allowing them a fine place to grow up. He slurs a little, makes a few mistakes, forgets a few things, and we connect with him, because he's human! His wife is facepalming a bit, but it's earnest, and it builds character.
Suddenly, The Event happens and we care about what happens to this guy! We relate to him! By extension, we care about his family, and all the other people on the island, because they've been established as people, instead of a statistic.
Not doing this is emotionally manipulative; we're meant to care because they're people. But they're not, because they're just a number that we haven't gotten to know. This is especially egregious as, no offense, you're a new GM to the game, which means the players haven't had a chance to develop trust in your style, which is a recurring problem in this explanation.
The argument could be made that the character cares, so I should care. But that's not how it works. It's killing my character's parents at the beginning of the story, when I haven't gotten a chance to know them yet. They've had no development. And if I don't care, I can't put feeling into my posts.
Problem #2 - Diabolus Ex Machina
There are no stakes. No tension was built. We're told straight away that we have no hope of winning. So, I don't care about the situation.
The Victims problem relates to this in that they haven't been developed. Likewise, we haven't yet been made to care about the island, and we haven't had a chance to get attached to it. So, instead of feeling like a loss of my character's home, it feels like a scenery change that I'm supposed to force empathy for.
No tension; there was no subtle continuation of the evening, where perhaps Marcus was called off to the side to discuss something briefly. There were no ships on the horizon for us to look at and wonder about. None of the people who were meant to protect the island did that; no calls on the radio, despite the fact that security is on high alert. Just, boom, suddenly there's a bunch of dudes inexplicably murdering people. No explanation.
In a game where I trust the storyteller, who has let us figure out such clues before and discover the mysteries, I would be able to go along with it. But I don't, which is no fault of yours, but is a result of the sudden ST switch. Instead of becoming a mystery for us to solve, it feels like something pulled out of hammerspace so we can be screwed over.
Then, the final thing, is that there's no hope of success. There never was, because we were told in the very first post with a new ST that we lose. The leaders of La Famiglia fled, and we couldn't stay or do anything to stop it. It completely removes any player agency, without an illusion of choice. There can be no happy without sad, and there can be no despair without hope. Snatch it away or have Moreno's troops beat it out of us, but don't tell us that we've failed before we can try.
It's a surefire way to make a player not care about what's happening.