The flotilla raid happened because Israel (and to some extent Egypt) are controlling what enters Gaza to try to prevent weapons from being smuggled into Gaza. The explicit purpose of the flotilla was to break the blockade. More than one ship was raided. The only one where people were killed was the one where the people fought.
The United Nations should control the maritime area around the Gaza Strip. It should be their responsibility to prevent weapons from being smuggled in to Gaza. Israel should be kept out of that part of the world.