This 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 Warand the subsequent disintegration of the Armed Forces, they became pirates in order to protect their waters. This belief is also reflected in the names taken on by some of the pirate networks, such as the National Volunteer Coast Guard (NVCG). [5]
I personally believe that this is pure rationalization on the part of groups of greedy rogue thugs.
Len