As the U.S. special forces team cleared the vessel, it discovered two pirates who already were dead. Another two were killed by U.S. personnel, one by gunfire and one by a knife, Fox said.

"A pirate was killed by a special operations force members with a knife while clearing the interior of the vessel," Fox said.

Its time to(in order):

 A. Find 15 lengths of manila rope.
 B. Give the yard arms a weight test.
 C. Feed the fish.

but "known pirated waters" just happens to contain one of the most important shipping routes in the world, if not the most important.

"Rear Admiral Charles Gaouette, deputy commander of the US navy's fifth fleet, said those on board were part of a group that had set sail from the southern tip of India. The vessel had apparently been bound for Oman."

If you look at a map, that is nowhere near Somalia.  It's on the other side of the Arabian Peninsula entirely.

As to the existence of the Somalian variety, from Wikipedia:

A United Nations report and several news sources have suggested that piracy off the coast of Somalia is caused in part by illegal fishing and the dumping of toxic waste in Somali waters by foreign vessels that have, according to Somali fishermen, severely constrained the ability of locals to earn a living and forced many to turn to piracy instead.[4][5] Other articles allege that 70 percent of the local coastal communities "strongly support the piracy as a form of national defense of the country's territorial waters", and that the pirates believe they are protecting their fishing grounds and exacting justice and compensation for the marine resources stolen.[6][7][8] Some pirates have suggested that, in the absence of an effective national coast guard following the outbreak of the Somali Civil War and the subsequent disintegration of the Armed Forces, they became pirates in order to protect their waters.