Smart Bosses, and despite his failings Bonanno was a smart Boss, always had a sociopath or 2 available to keep the troops in line and to keep the other families from taking liberties. Costello had Moretti and then Anastasia and Bonanno was apparently tight with the Mad Hatter. Luciano of course had Genovese, a man who liked to throw guys off tall buildings so he could marry their widow.

I guess Galante was also the ideal man to deal with the wild Canadian drug dealers in Joe B's eyes.