Seems very possible that there was a similar approach here in Vietnam where a goal might have been to get the stuff to the US.

I'm a bit confused by the seizure. Ie, if US doesn't want the cheap aluminum -> let another country have it cheap?

That said, Biden does seem to be going big on tariffs.

"The decision is one of Mr. Biden’s first significant moves on trade and suggests that his administration may be inclined to maintain the type of hefty tariffs Mr. Trump imposed on foreign metals to protect domestic industry. That position found favor with unions, but disappointed industries and businesses that have argued the tariffs raise costs." - NY Times - Biden Reinstates Aluminum Tariffs in One of His First Trade Moves

So this story does seem to be continuing with efforts by Biden to keep imported prices higher and there may be an element of politics in some of this all.