That is the reason European countries do not block Russian oil exports. There are sanctions and if there is any chance of stoping a ship in line with international law is being used. However it is not a full blockade.
What the US is doing to Cuba is not a “blockade” either, in the dictionary definition. The US is just sanctioning the shit out of anybody who sells oil to Cuba. Which is evil, but legal under international law.
I am not sure about legal as it is causing civilian death. It is a grey area and in violation of human rights and international humanitarian law. Of course no one is really enforcing these against the US sooo…
Possibly. But at least it is a grey area, not obviously illegal. Unlike e.g. Iran shooting random third party civilian ships in an international shipping lane, which is unambiguously illegal.
No the US is taking ships sailing oil to Cuba. It is not just sanctions.
Incorrect I think. There was that one Greek ship, but I think the US just threatened it with sanctions, not boarded it.
Wikipedia has a long list of sources for US seizures of oil tankers sailing to Cuba: en.wikipedia.org/…/United_States_oil_blockade_dur…
United States oil blockade during Operation Southern Spear - Wikipedia

  • So taking the first one on that list:

Moments before the seizure, the tanker was flying the Guyanese flag, despite not being registered in that country.

It is legal to seize ships flying a false flag. So that seizure was not an illegal blockade by the US.

  • Second one is a Venezuelan one, which fair enough the US is acting illegally in all kinds of ways with Venezuela, nobody serious disputes that.

  • Third one was a Panama flagged ship, and “Permission to board was obtained from Panama”. So boarding that was legal.

Etc etc I assume.