First, the IDF is not firing indiscriminately. The IDF has warned civilians to evacuate areas where it is planning operations. Were it not for this advance warning, there would be many more casualties. Second, most unfortunately, Hizbollah hides among the population. They hide weapons, and missiles in houses and other civilian areas, such as mosques, and therefore it is impossible to avoid all civilian damage. Third, a lot of the bombings have been against dual purpose facilities such as the airports and roads to Syria which can be used to bring in more rockets.
Turkey launches heaviest air strikes on PKK since campaign began, official says (Reuters)
from the article: Firepower versus brainpower