There has been one fatal bear attack in the United States this year. Meanwhile, if this is a typical year, there have been nearly 23,000 killed on the highways (including 4 fatalities in Alaska the day before in two incidents within a few miles and a few hours of each other) 12,250 dead from falls, 2,300 drowned and 17 people KILLED by dogs.
The widespread report of this attack and other bear attacks says more about how relatively rare it is rather than how common it is.
Here are some real-world stats on what killed people in the backcountry in 2010: http://www.edarnell.com/Stats.htm Many years bears wouldn't appear on such a list at all. Every year bears would be way down the list.
It sounds to me like those teens did just about everything right. Sometimes life is risky and things go wrong.