The threw the commandos overboard, knifed them, had clubs at the ready to hit them with, stole their guns and used to shoot at the commandos - all before they fought back.
The ship was trying to run the blockade and they were perfectly legal in boarding a ship in international waters if after warnings or repeated failure to hail do not work if the ship attempts to progress through the blockade.
And they plan on stopping more ships that attempt to run the blockade. More power to them.
And to think they could have easily just went to the nearby Egyptian port to deliver their 'humanitarian' goods and none of this would have never happened. When the British put a blockade on us during the War of 1812 - boarding was the least of the worries, they just blew the ships out the water. But eh, we have nice wars now I guess.