Ah. OK. Thank you ...
To answer your question: there is no crime, because the targets are stateless, flagless vessels operating on the high seas in violation of the laws of every nation. They have the same legal status as pirates: fit only to be blown out of the water, with the survivors hanged from the nearest yardarm.
While the US Navy seems to be doing a good job, I remind one and all that the Congress still has the power to issue, and the President to sign, letters of marque and reprisal.
A Captain of a US warship is REQUIRED to interdict in acts of piracy. An unflagged vessel transporting contraband is an act of piracy.
There's no prize money associated with this. No way to make it a desirable business.