it's because they never arrest those responsible. knowing that nobody ever intervenes to bring them to justice they continue to commit murder after murder, with the complicity of an indifferent and unapologetic government. the government should be held responsible too for allowing so murders to take place.
Prominent Druze sheikh al-Balous killed in Syria (Haaretz)
from the article: PA accuses Israel of killing Palestinian teens 'in cold blood'