Nothing much to explain. It's just a balance Asobimo made for this class. Minstrels now have the capability to "solo," but at a cost, range cut was reduced a lot and all songs, now since do damage, are active skills that only work targeting a mob.
Basically, Minstrels songs are no longer a full "support" skill that's able to be used outside of battle. Minstrels skills are like any attack skill now.