I appreciated the bit where she acknowledged she'd been writing a stereotypical snarky, judgmental Slate article up to that point. Unfortunately by that point, the article was nearly finished, and there wasn't time to recover from it. I'm not sure what I should be taking away from this article: seems like not much happened, but they had to write a certain number of words about it anyway.

So, the author was desperate to find something tacky and lambaste it.

The author found that it was simply groups of people who like doing stuff together, for various reasons.

The Gone Girl element was just a decoration on the cruise, to get people talking about it, or perhaps to make it more interesting to talk about it.