An Honest Question

I am confused. This is not tongue in cheek. I am genuinely confused.

It is about the Israeli navy boarding the Turkish vessel which resulted in nine people on the Turkish vessel being killed.

As I understand the agreed facts, the Turkish vessel was sailing toward Gaza, but still in international waters, when the Israeli navy contacted it and asked it for its destination. The Turkish vessel responded that it was headed for Gaza. Whereupon, the Israeli navy forcibly boarded the vessel, a fight ensued, and nine people on the Turkish vessel were killed. The Israeli navy then took possession of the Turkish vessel and forced it into an Israeli harbor.

I'm not asking about the moral or legal right of Israel to defend itself, or the moral or legal right for it to impose a blockade on Gaza, or the moral or legal right for Israel to board a ship that is in the waters of Israel or the waters of Gaza.

I'm not even asking about Israel's moral right to board a Turkish vessel in international waters after that vessel has admitted it was headed for Gaza, then commandeer the vessel and take its cargo.

I'm asking about the legal right for the Israeli navy to forcibly board a Turkish vessel in international waters.

If I understand the international law of the sea, no nation has the right to board the vessel of another nation in international waters without permission. As I understand that law, if a private vessel or person does it, it's piracy. If a nation does it, it's an act of war.

But, I don't hear anyone saying, "Wherever the moral or ethical chips may fall in this matter, Israel did not have the legal right to board a vessel flying the Turkish flag in international waters." And I don't understand why I don't hear anyone saying that.

What am I missing here?