Show me the article in said "maritime law" that says that.
It has been a while since I studied international law, but this should be fun.
Strictly speaking, none of what you posted constities an act of war in any way shape or form, but capturing a vessel traveling under another nations flag in international waters, now that is an act of war.
The Israeli actions were an armed attack on a vessel travelling under the flag of a Nato member state as defined in article 6 of the NATO treaty which should, in accordance with the article 51 of the Charta of United Nations and article 5 of teh NATO treaty lead to automatic aid and assistance of all NATO members to the attacked NATO member, in this case Turky.
Just for shits and giggles, let us look up what an act of war actually is, according to USC 18 Â§ 2331:
(4) the term â??act of warâ?? means any act occurring in the course ofâ??
(A) declared war;
(B) armed conflict, whether or not war has been declared, between two or more nations; or
(C) armed conflict between military forces of any origin; and
So, we either need a nation state or at least a military AND an armed conflict for an act of war, so just to make this very clear:
Travelling in international waters is not an act of war.
Declaring Jihad, if declared by a civilian is not an act of war.
9-11 was no act of war.
Crossing the US border is not an act of war, unless you do it in a tank, as part of an army.
Killing US border patrols, also not an act of war, neither is selling drugs, money laundering, posting threats on the internet or whatever else gets to be called an "act of war" these days.