I don't follow.While I agree with you a lot, that situation you just typed is exactly what happened with the U.S. and Japan.A blockade is an act of war. As such, it opens the door for a military response.
The correct response to any such closure is the removal of the assets that affect said closure. This will require a number of repeated air/missile strikes combined with some limited number of boots on the ground, certainly to include SF personell and, likely, some small-unit raids.
Few can legitimately oppose such action - the only real question is if the necessary people will support it and then act on it.
Which, applying the same logic, would mean that Japan's attack on Pearl Harbor was justified.
An embargo isn't a reason for war, it's just business. Yeah it would suck, but it's their choice, just like our embargo wasn't an act of war, it was just business.
Causes of World War II in the Pacific - World War II Causes - Cause of World War with Japan.
Moving Towards War with the US
The American oil embargo caused a crisis in Japan. Reliant on the US for 80% of its oil, the Japanese were forced to decide between withdrawaling from China, negotiating an end to the conflict, or going to war to obtain the needed resources elsewhere.