I think they were in college, so how old they were depends on where they were. (In Britain, college is 16-18, in America I think it's 18-21, if anyone knows better, feel free to correct me.) I think people that age should have some sort of grip on the horrors of war. My favourite TV show was a kids' cartoon about a war, and while there was a clear villain, it was explored in a lot of complexity, and is enjoyed by adults as well as children. And yes, the article did mention sci-fi, fantasy, and historical fiction.