اسرائيل قد تلجأ للقوة لمنع سفينة تحمل علم فنلندا من بلوغ غزة

So that there would be no mis-understanding Israel informed Finland of its intended action.
If Finland is so worried, even though from the report it seems that mosat of the people on board are not Finns, they could have arranged for the ship to be stopped at any one of the ports it stopped at en-route.
Why did the Canada's Gaza's Ark group not have a ship flying the Canadian flag? Because they know that the Canadian authorities would have done everything in their power to stop this escapade. Whereas, the Finnish Government allows this to go ahead and then cries wolf. concerned

Those masts could be camouflaged surface-to-air missiles. Israeli military policy is like the shoe-polish on an SS (Schuetzstaffel: "Body-guard-corps") officer's riding boots. The boots were useless in the age of the internal combustion engine and the polished shine added little to military efficiency and even less to the welfare of the state or the people in the grip, as they were, of a suicidal national government, but the stylishness of the officer's costume was itself the policy, as if to say: we walk through the sewage of our enemies's meaningless lives and not even our shoes get soiled.
I'll bet most Germans said to themselves in 1946, "I can't believe we lost the war--we had every advantage on our side!" And then most of them said to themselves, "My God, is there no end to my depravity?"