IDF attack Gaza Flotilla

The video below seems to clearly show IDF  commandos being attacked by passengers on the boarded vessel. But the question remains. Why did The  Israeli defense force handle the situation the way it did. It could have created a naval blockade.
I remember in the 70's when I lived in Israel. There was a Guy called Abbi Nathan who captained  a vessel called 'The Voice of Peace'. The voice of Peace was a pirate radio ship, anchored off the Israeli coast it pumped out the best music in the middle east. The crew were made up of both Jewish and Arab members. Abby Nathan was a peace activist i.e. he put his own life at risk to help bring peace but NEVER retaliated.
One time Abby collected flowers from Israelis residents and tried to deliver them to the Egyptians. He flew a light plane into Syrian air space. He used to ask us to flash our headlights if we wanted peace.
He was a true peace activist. Once violence is used except in self defense  the right to be called a peace activist is gone.
Did the members of the flotilla heading for Gaza think they could beat off the IDF with sticks and bars. I don't think so. I believe that the activists on the vessels were ready to attack the IDF. To increase sympathy from other nations to stop the blockade of Gaza. The big question then is why did the IDF attack at night in international waters  a situation  which almost certainly would end in deaths.