This striking thought just came into my mind.
Our Lord Jesus Christ said: "Concerning that day and hour, nobody knows, neither the angels of the heavens nor the Son, but only the Father. For just as the days of Noah were, so the presence of the Son of man will be." Matthew 24: 36-37 (Revised New World Translation or RNWT)
In Acts 1:6, 7: "So when they have assembled, they asked him: "Lord, are you restoring the kingdom to Israel at this time?" He said to them: "It does not belong to you to know the times or seasons that the Father has placed to his own jurisdiction."
The message is clear from both verses: Only the Father knows that day - the presence or coming of the Son of Man - whichever way you want to put it.
That being said, if the Governing Body or faithful slave has exactly identified 1914 as the start of Christ's ruling or his invisible ruling in heaven has begun, would that not be too presumptuous of them? Would that be beyond pure speculation - more than what the apostles had wished?
In effect, if the GB has identified this date which, according to Jesus Christ his Father only knows, then that makes the GB more knowledgeable than Jesus, the head of the congregation. In simple terms, if the Father only has the knowledge when that momentous day will come - whether Jesus' second coming or his presence - then who is the GB to determine it with sharp precision, much less teach it as an absolute truth?