Well yeah, there's a reason for that. Joe and Bill made a pretty concerted effort in their biographies to make themselves out to be Vito and Michael Corleone and the Bonnano family in to a nostalgic, quirky but yet honorable Sicilian tradition. Mentioning the psychopathic drug dealer they employed would have ruined that image. Galante was in to drugs his whole career and if there was a "no drugs" policy while Bonanno was boss, he wouldn't have gotten to where he was by the 1950s.

Bonanno was up to his eyeballs in heroin. Contrary to the myths surrounding the age, most families at least dabbled in or tolerated drugs as long as made guys didn't get caught with it.