Israel on the high seas.

[halfbaked]

First of all i would like to say that in the trans-boundary waters apply also some laws. The international waters are 200 sea miles away from the land and the flotilla were attacked in the international waters.
Read:

Ships sailing the high seas are generally under the jurisdiction of the flag state; however, when a ship is involved in certain criminal acts, such as piracy, any nation can exercise jurisdiction under the doctrine of hostis humani generis.

That's the first crime they commit. They attacked a ship that was sailing under the turkisch flag, not a pirate, a country in peace with Israel. That's an act of war. The people of that ships have the right to refuse the soldiers on their ships.
Israel is on the whole line wrong in this case.

The second crime they committed was that they bordered ship with weapons, in this case they were the pirates, licenced by their government, but still pirates. Israel didnt decleared that ships to pirateships, so they attacked a harmless civilianship of an ally.