Historically, there was something of a divide in the family between the Sicilians and the Calabrians. When Joe Rugnetta was consigliere he didn't just function as a mediator but as the head of the Calabrians in the family (in the late 1960s, Rugnetta and other figures refused to go to New Jersey for a making ceremony because none of the proposed members were Calabrians).
Caponigro was the choice of the Calabrian faction to replace Rugnetta, hence why he got the position