The Whitey and the Billy

My American I was born in Boston, and in those early years I would glue my ears to the radio for clues on both the language and the culture that makes e pluribus unum.
One surname was the source of deep confusion: Bulger. I would sometimes hear it in the crime section, at other times in politics. The given name did not help much, and it took me a long while to distinguish two. Little I knew that one, William Michael "Billy" Bulger was the president of the Massachusetts Senate, and the other, James Joseph "Whitey" Bulger, was the "president" of the Irish mob (in fairness to my sticky ears, such names were never enunciated at full length). It took me even longer, and I still find it hard to believe that these two do not share a surname by coincidence, but are related, and in fact brothers.
These memories lay dormant until today, when I heard of the capture of the Whitey. Hearing that the FBI is still after the mob and that nabbing its fugitives still makes news is a salve for a mind somewhat chafed in the times of Bin Laden and cyberwar. 
That two scions of the same stock can grow so contrary to each other, like faces of a family Janus, like William Wilson, is yet another reminder that human nature is still manifold and irreducible as ever.