This stupid bickering about "mooslims" and "fear mongering" leads me to conclude that few of you actually read the OP's article. It's a pretty sober assessment, and perhaps not quite as alarmist as the OP interprets it to be. The author points out something that surprises me - that likely not one person would die from radiation spewed by a dirty bomb. Doesn't sound a lot like fear-mongering to me. Moreover, it discusses evidence of international trafficking that is at least concerning enough to not dismiss.
Most importantly, the author suggests several courses of action to reduce future threats that are pretty sensible, like coopering more fully with Russia in both nations securing their waste and fissile materials, putting more funding into prevention of international trafficking in fissile and radioactive materials, etc. These are things that no sane person should oppose. They are things that we should be wondering why they are not being done already.
In truth, I think the near term threat is extremely low, as the author pretty much admits. But in the long run? Perhaps there is cause for concern, particularly when we decide to dismiss completely reasonable suggestions on something as important as nuclear security as "fear mongering" about "mooslims."