This is actually part of the shipping failure. Does Amazon have different ports and different workers unloading things? Read the article and you will see the answer is no.

What Amazon has bought is priority within the massive shipping complex (with ships and port both controlled by the 3-4 cartels). There's nothing they've accomplished here except get an immunity to the problems that actually means the delays get shunted onto other organizations trying to get their stuff. Basically, the very largest monopolies are protecting each other and screwing the medium-sized and little guy operator.

Is Amazon using the Port of Oakland when LA is ultra-busy? No, Amazon stuff is going quick through LA and this automatically means other stuff is going slower.