The basic thrust of Cameron's argument was to deconstruct the Watchtower's claim that they were serving the kind of "proper food" at the "proper time" that would pass Christ's inspection.
As he points out rather succinctly, the Watchtower was not publishing proper information at the time of the supposed inspection of Christ. Their teachings did not differ much from that of the Second Adventists of the time. At the time of the supposed inspection by Christ Jesus, they were still teaching that Jesus was enthroned in 1874 - another carry over from the Adventist movement.
The very foundation of the "Faithful Slave" teaching comes down to the 1919 appointment by Christ. Regardless of what has been taught in the last 90 years, the question remains - did this divine "selection" really take place. As Cameron points out (through pointing out all of their sloppy teachings at the time); the "spiritual food" being served at that time was hardly anything to be proud of; and with all of the falshoods that it contained; was nothing that could be considered to be superior over other Adventist-style groups.
Ray Franz in his book In Search of Christian Freedom, devoted an entire chapter to the concept of the Faithful Slave with it's 1919 appointment. After considering all of the evidence, Franz very bluntly referred to the published teachings as "immaginative silliness". He also stated that it was "an insult to Christ Jesus" to claim that he had chosen this organization based upon what they were publishing at this time.
No wonder Kingdom Hall libraries have purged all of the works by Russell and Rutherford. If all of the teachings of the time were so illustrious as to garner Christ's favor; why is it that these published books can only be found in "apostates" attics and on E-bay?