There was 500 people on board to express solidarity with the cause and the mission, these activists were from all over the world, as soon as Israel arrests them their home countries have to be informed and the process of deportation operated.
All this means that the home nation of the protestor has to make a statement or express a position with regard to it's citizen, it also means that the national news papers of the protestor's nation will remark upon it in greater detail as it has a national "local" interest.
These troops are highly trained, equppied and armoured rubber or plastic bullets could easily have been employed.
Israel's made a minor faux pas in all this, the protestors wanted them to react violently to it, and the obliged.
It is a minor incident as noone'll do anything about it other than beat their gums for a bit.
Although Turkey does take over the chair of the security council next week, so that will give it a bit of spice.