First, they talk about asteroids like they're just a risk to be calculated. The problem is that a large enough asteroid wouldn't just kill a lot of people, it would be the end of civilization as we know it, and quite likely would cause the extinction of humans. So even if the odds are low, the consequences are bad enough that we should be worried about it. Also, it's not like it hasn't happened before. An asteroid hurt a bunch of people in Russia a few years ago, and a really big one killed off most of the dinosaurs in the K-T Event. The dinosaurs learned the hard way how foolhardy it is to not have a strong space program.
Second, a danger like this is good for us as a species right now, if we take it seriously. We need to get into space for a lot of reasons; we're destroying our ecosystem, using up our resources, polluting the planet, and there's no end in sight. There's huge opportunities in space: there's untold resources ready to be mined in asteroids or on the Moon nearby, and if we could come up with the technology, we could even live there just in case this planet becomes uninhabitable. However, if we wait around until it's too late, we won't be able to take advantage of space-based resources (or deflect a killer asteroid); we have to start now, developing our capabilities.
Finally, a threat like this is good for us to focus on, because it gives us a reason to be more unified. We humans are stupid and fight with each other when there's no external threat; the only time we band together is when there's an even bigger external threat which forces us to look past our differences and work together. Killer asteroids are good for that, forcing us to develop our space technology without needing to demonize some other group of people.
Honestly, the authors of this article should be ashamed of themselves. Even if they were right, they shouldn't publicly proclaim this because of the negative effects on society. What would they rather we do, give up on space technologies and work instead on building more ground-based weapons systems so we can fight each other more and pollute our ecosystem even more? Good job, assholes.