> And they can certainly deem oil contraband if they are allowed to do food and medicine, as quoted.
Wikipedia is defining what the term blockade means not what constitutes a legal blockade.
Medicine is not allowed to be blockaded. Food is not allowed to be blockaded if there is a shortage.
Relavent parts of the san remo manual:
> 102 The declaration or establishment of a blockade is prohibited if:
> (a) it has the sole purpose of starving the civilian population or denying it other objects essential for its survival; or
> (b) the damage to the civilian population is, or may be expected to be, excessive in relation to the concrete and direct military advantage anticipated from the blockade.
> 103. If the civilian population of the blockaded territory is inadequately provided with food and other objects essential for its survival, the blockading party must provide for free passage of such foodstuffs and other essential supplies, subject to...
> 104. The blockading belligerent shall allow the passage of medical supplies for the civilian population or for the wounded and sick members of armed forces,...
https://ihl-databases.icrc.org/en/ihl-treaties/san-remo-manu...
You're correct that blocking oil would be allowed (barring situations where the civilian population needs it to survive, which doesnt apply here) if this was a legal blockade. However Iran is not complying with the other rules around blockades, which is the issue.
