In Egil’s Saga, the Vikings were described as merchants.
I would agree that the vikings had a different set of beliefs and morals than the rest of the people of that time. I guess if you compare them to the pirates of today you could see some similarities. They both are doing this for economic gain.
The author is merely concluding that the Vikings' motivations were largely economic, and that raiding and pillaging were the most economically viable option open to them. I don't know if you can say the Vikings had an "absence of awareness" of wrongdoing or morality, I think they simply had a different set of values, more in line with their culture and the time in which they lived. It's not as though they did not have some rather strictly observed cultural rules and laws within their civilization. Without such rules and laws, it would have been anarchy.
I also don't know that you can describe Somali pirates as "evil". It's a very strong term, and the kind of violent crimes they commit, while the rest of the world still has a right to defend themselves against, can largely be traced back to a country that has virtually no economic and political hope in the near term, and to a generation of people who have grown up amidst that lack of hope. They believe they will not live to see 30, and that the ends justify the means in their desperate situation. It's horrible to witness, as are their crimes, but I don't think "evil" comes into it as much as you might think.