Iran clearly should have warned all vessels in international waters long before the missile launch. The last thing either side wants is some kind of flair up that would lead to a standoff between the two countries.

The US protested that firing, but it was fired AWAY from the US Carrier. While the US Carriers was in international waters, it is unclear if the Iranian ships were in Iranian waters or international waters. At that point in the Gulf those can be within 1500 meters. And the only significant difference between the two is how much warning a nation has to provide. No notice in domestic waters and if I remember right, two weeks notice for international waters. Iran had the right to do what it did, the US protest was that Iran only gave a 24 minute warning of the maneuvers. Such a short notice implies this was in Iranian domestic waters.

Anyway this sanctions is for Iranian LAND BASED ballistic missiles not ship to ship missiles as were used in the above incident. Iran is developing missiles that can launch satellites into space and such missiles can also reach any place on the globe with a nuclear device. That is the rationale for the proposed US sanctions not the firing of a ship to ship missile.

Please note Israel already has such missiles and can use them to hit targets with massive conventional high explosives warheads. Iran appear to be developing a similar missile. A missile that could hit Israel with a massive high explosives loaded warhead or launch spy satellites into space to spy on Israel or even the US Navy operating near Iran.