It was owned by a Greek company. Iran never owned this boat. This is just tit-for-tat bs to be obnoxious.
Iran did hire this boat to evade sanctions. Got caught. The operator pled guilty and paid a fine. The oil was seized. But the boat was given back to the Greek owners.
Stealing Iraqi oil sold to Turkey because it’s on the same boat seems like the actions of a petulant child. But that said it’s all Iran can do. They know going against the US directly will end poorly no matter how much they want to posture. Which is why they’re paying the Houthis to be their cannon fodder.