It seems a bit shortsighted, to me. It seems to me that they could and should be more heavily armed than they are ... but I think the same of truly civilian cargo ships, as well.
Life is one big game of chess. If you are safe behind your defences, say in the USA, or enroute to Hawaii or non-war zone areas - you can have your cargo ships go about their business without an armed escort.
But, the area of the world we are talking about is well known to be a dangerous area. In the USAF, we send a fighter escort with our bombers. If we have essentail cargo moving though an area, we either provide air support, or we are at 'standby' until those cargo aircraft are through any perceived dangerous airspace.
Silly me, I assumed that the Navy would have more than a passing interest in protecting a fellow Navy cargo ship. If they can ignore a USNS cargo ship that is under attack, they will most certainly ignore a commercial ship with an American flag that is similarily under attack- right?
Here's what I expected to happen. There is a US Navy battleship somewhere. A US Navy cargo ship (unarmed) reports being attacked by pirates. A predator-type aircraft uses downlooking radar to identify the ships. Either aircraft are launched, or a missle is fired, or the UAV engages the pirates and they are decimated. Message sent, don't mess with the Americans.
Obviously, we now look like cowards to the Somali pirates. We did not make any 'good impressions' with our enemies all over the world. We look weak and cowardly. This event, coupled with Pres. Zero's embarassing foreign policy disasters has certainly tarnished the Navy's outstanding reputation.
Please do not misunderstand - I have nothing but the most absolute respect and admiration of those men and women who serve in our armed services, including the Navy. I just find this event particularily disturbing.