Terrorism have been in this world for a long period of time. No human attacks other human until or unless they have harmed them. Blaming some community or some religion isn't good just on the basis of that person belonged to that community its not the fault of those insolent people . No one relies until it happens with them. Every one in this world have different prospective and non one is wrong in this world. Its just how everyone one see's this world.
Terrorism is wrong because it causes other people suffering when they have not done anything wrong and were simply trying to live their everyday lives. Violence is not a productive way to solve a problem and there are many other ways to sort out arguments between people with different views.