During the Cold War, America used various shell companies to get valuable titanium out of Russia for building spy planes. If someone is willing to pay, smugglers will find a way.

Simply banning things causes the price to go up. That alone is good enough to motivate the policy decision.

Export controls inherently raise the cost of doing business with parties you don't like, the other party has to either invest more resources acquiring them, or make the decision to forego acquiring them. The grey market exists precisely because there's an opportunity to exploit this for profit. At the end of the day, when these effects of these export controls are discussed, they usually seem to revolve around export controls setting a specific program or effort back by a span of months, not in stopping a specific commodity from accessing another market whatsoever (excepting some hyper-specific components).

> its pretty much uncontrollable

As Hezbollah discovered in 2024, covert supply-chain interdiction is very possible and I'd be surprised if the CIA didn't know what was going on, at least to some extent.