I don't think customs "made" OP miss his flight. As potentially an inexperienced traveler, he probably asked a customs officer what to do if his bag hadn't arrived and they told him he should wait for it. Which I think is the "correct" answer, at least until it's confirmed that the bag did not arrive on the flight.

Most of us would know just to go make our connection and deal with the bag later.

So arguably the misdirected bag "made" him miss the flight. Isn't positive bag matching still required on international flights? If so, this might be something the FAA or DOT would like to hear about, and perhaps that provides leverage in compensation negotiations with DL?