That pushes the question to "why did users flag it," but it's not hard to speculate reasons why. A dedicated minority roll their eyes at discussions of AI safety. On top of that, although the article itself is sound, it's targeted at non-technical people, and the domain it's hosted on isn't well-regarded (trending banner on top: "What happens when you hold in a fart?")
At the end of the paper, they mention "three factors over which the crowdfunding founder has complete control: the goal, the number of reward options and the duration. To maximize the likelihood of success, Fig. 1 implies that all other things being equal, a founder should choose a Log(goal) which is less than 7, a number of reward options which is at least 40 and a duration of between 10 and 15 days."