Modern day piracy.
Iran and Israel had friendly relations and viewed each other as allies, until 1979. I'm not kidding. Iran and Israel cooperated on joint-military projects, such as the Project Flower missile project [0]. Israel used to manage Iran's oil production.
Iran's leadership changed post-1979, relations soured, and Iran began spending billions of dollars per year funding terror groups to destabilize Israel. Hezbollah in Lebanon receives $700 million per year from Iran. Hamas and other groups in Palestine receive $100 million per year. The Houthis in Yemen are supported similarly. Iraqi proxies receive an estimated $150 million per year. Iran has invested tens of billions into supporting regional proxies against Israel.
Naturally, these hostile foreign policy choices create enemies. These policies aggravate Israel. And since the US is an ally of Israel, the US is also dragged into the conflict.
Iran could have easily completely avoided the situation it finds itself in.
If that happens, a lot of countries will give very serious thought to attacking each other, not just in the middle east, and may decide they don't have a choice.
So the Strait has no clear legal status.
In theory since Iran didn't ratify UNCLOS they can only claim 3nm of territorial water, but they claim 12nm anyhow.
The USA insists on the right of transit passage, but itself isn't even a signatory to UNCLOS so that's hypocritical and has no basis.
It's a mess that nobody wants to touch, so it's pretty much up for grabs by the most militant player.
It's whoever has the will and the mean.
The more I see of that war, the more I think a war was/is necessary because we can't let these lunatics have nuclear weapon. Whatever the cost.
I found this detailed article [0], written by a law student, which discusses the Hormuz strait situation in the context of the past century of maritime law.
[0] https://www.lawfaremedia.org/article/the-strait-of-hormuz-an...
In any other legal situation, if the supreme court says it's OK, there's nothing to be done. There's a word for that: legal. As in whatever happens is legal, even if everyone kills each other.
That's what the world voted. That's the situation "international diplomacy" has chosen.
There's not much relevant to be said about maritime law until the US wins (because Iran won't respect it, regardless of what it says)
If these treaties are not in force, a lot of countries cannot trade freely internationally. These days all countries are dependent on free international trade, but for obvious reasons it goes double for desert countries like the ones behind the strait of Hormuz, even without considering oil.
Geography allows a number of countries like Iran, but also Spain, Indonesia, South Africa, Argentina, Turkey, UK, Denmark and Yemen to tax entire continents, including each other simply by threat of sinking ships. Endless wars have been fought over this.
Why?
First, anything that depends on international supply chains (like computers, iphones, cars, coffee, chocolate, tea, ... or the food for the survival of gulf nations' populations) is gone, in a matter of months.
Second, the "Pax Americana" is over, the post-WW2 security architecture is over (which is code for WW3 will start as soon as the first country considers itself ready). This will, by the way, not fix the first problem, not even if your country wins.
The sad truth is that either the US wins this war, or half of the world will once again find their place of employment is a cold, wet dugout with people shooting at them. Including, of course, Iranians.
It's not international waters.
> if Iran is allowed to do this
They have sovereignty and they only ever mentioned doing this to pay for reparations after being attacked by two countries that have been allowed to routinely attack/exploit the Middle East and, in the case of one, carry out genocide.
As an aside, the war is largely seen as being waged for the sake of Israel, against US/world interests.
> Indonesia will tax the Malacca strait... a lot of countries... attacking each other
Pure fearmongering, in no way different from "think of the children and of the terrorists".
Iran maintains a blockade on the strait by placing mines in Omani waters, and firing missiles at civilian ships that attempt to pass in Omani waters. It has no legal basis to do either of those.