The article fals to mention that everytime the long named volcano erupts, it melts the ice of the neighboring one and it goes off. The neighboring one is the real problem.
Actually the real danger is not just the Hekla might go off, but that the fissure could be extensive and erupt for months at a time. The Laki Fissure event of 1783 had just such behavior and caused terrible problem for Iceland and also in Europe. See the link below for more information about this famous event.