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!!!
British foreign secretary: There is no immediate threat to Europe from ISIS bases in Libya (Reuters)
from the article: Video: Gaza flotilla activists attacking Israel Navy commandos