I don't believe your claim that governments ask for something like a metal spectrometer analysis, especially since Digikey hasn't reported the same disruptions. There's no way Digikey did this for all 16.5 million parts.

In later comments on their blog they admitted they didn't even file the paperwork and left it up to the customer, who obviously wouldn't know how, causing the part to get stuck in customs.

It's a frustrating situation for them but there's no way CBP is making people break out lab equipment to import a PCB.