Isreal shot several shots before they descended upon the ship, that is why the activitist thought they need to defend themselves, and thus attacked the IDF. Also, why didn't they shoot the activists below the waist so that they can scripple them without killing them. But the truth is that the IDF wanted to make an example out of them. Just a couple of thoughts!!!
Judge sets $1m bond for Ohio officer charged in murder of unarmed African-American (Reuters)
from the article: Video: Gaza flotilla activists attacking Israel Navy commandos