It is far from likely that it was a purposeful lie because of the guarded language used in presenting what may be termed the “last of the great dates” set by the Jehovah’s Witnesses.
It was already a significant teaching that the end of the world had to arrive before the generation of 1914 passed away. Their self-identity of the restoration of true religion at the end of the world depended on it (and remember, that is the reason the Witnesses came about, not because the world needed true religion but because of their belief that at the world’s endtrue religion would be restored), and a little known “lost 100 years” in Adventism was still in the minds of the oldies like Franz that allowed them to reuse the old 1874 date.
1874 and the Lost 100 Years
Charles Taze Russell had emphasized the 1874 date as Christ’s invisible return based on an old Adventism belief that 6,000 years of humankind’s history (and the 6th creative day) came to an end in the autumn of that year. While the original 1874 date had others believing Christ would return visibly, Russell merely advanced the idea that parousia in Matthew 24 carried only an invisible presence as a meaning, which of course is not the exclusive meaning of the word.
Later when conservative Fundamentalist Bible theology suggested that Adventist’s dates were off by 100 years plus 1 (because of there not being a “zero” year between 1 A.D. and 1 B.C. that Adventists had trouble dealing with), Franz as well as others like Armstrong of the Worldwide Church of God did the simple math of adding 101 years to the 1874 date. Guess what? That lead to the 1975 date. (Armstrong himself published works pointing to 1975 as the date for the world's end.)
Did the Witnesses believe it was a lie? Of course not. It was basic Adventist time formula on which their religion had been literally founded. This was a means to prove Russell a true prophet (because if it turned out to be 1975, then it was only a slight calculation error for Russell) as well as the rest of the Governing Body (since they really believed that the Adventism restoration stories applied to themselves).
But to make sure that in case things did not turn out right (they had printed goofs before), they invented a double-speak for 1975. They used peculiar terms that would be easy to back out of such as how the end of these 6,000 years would be an “appropriate time” for God to bring Armageddon.
The Lost Connection: Public Discourses
While never saying blatantly in print that the date was a definitive one, the Governing Body fostered the excitement through the outlines of talks given at assemblies and conventions and directly through traveling overseers to congregations. The year 1975 was highlighted again and again in books and mags without anything precisely being printed, while allowing the rank and file to make the connection with what they heard from the platform.
Some new ones today are convinced that the Governing Body meant nothing by highlighting the year 1975. Others want to make it sound like unfaithful ones pushed ahead of the Faithful Slave Class by claiming they invented the end of the world connection on their own. But the truth of the matter is that the Governing Body wouldn’t be publishing things for the Witnesses to study that has no meaning. Why highlight 1975 in print but say nothing directly about it? Strange, no? Where would the rank and file have got the other information about the end of the world connection to 1975, and for all of them to have that same information that it meant the end of the world? Again it was those public discourses and what visiting overseers were given to push by word of mouth from the GB.
By allowing overseers to claim the “end of the world” connection with 1975 and then by printing so much with the literal date, the average Witness (for whom setting their own dates and making up doctrines or claims is strictly forbidden) did exactly as they were told: they put faith in and preached the coming end in 1975. If this was independent thinking there would have been other things connected to the date. Interestingly there is only one thing, the end of the world. For all "unfaithful" to "independently" come up with the exact same mistake without being told what to believe is highly unlikely, especially in an organization that is run like the Jehovah's Witnesses.
As today, Witnesses back them were much too timid to invent such a scenario and independently come up with a date like 1975 and what it could mean. For them to do so on such a large scale for almost a decade without the Governing Body ever calling any of them to task for it shows it was planned and totally believed in from the top all the way down (who ever heard of anyone being disfellowshipped for preaching that the end was going to come in 1975?—which would have been done if it was considered to be a non-Witness teaching by the Governing Body back then).
Only After 1975 Did the Lying Begin
It was only as they neared the end of 1975 did a few articles prepare people for a “just-in-case” situation. And then, without warning, there was nothing about 1975…until the mid 1980s when the cry against the Governing Body grew so loud (and people had to be disfellowshipped to basically keep others from hearing them) that the GB tried to pass the buck, claiming that "others" ran with a ball they hadn’t pitched.
The excuse didn’t fly this time, and other higher ups and respected ones like elders and overseers called the Governing Body to task. They eventually folded under the pressure and weakly allowed it to be printed that they were including themselves when claiming that people took the 1975 date further than they should have.
The following years of rewriting the event to the point that it is very hard to find the1975 outlines and articles (even banning cassette recordings of talks made at the conventions that were being passed around by the brothers in the 1980s—among which were recordings of the 1975 convention talks) was all done to cover the mistake. Allowing others to believe that “unfaithful ones carried it too far” and that “the JWs never said directly that the end was coming in 1975”—that is the real lie!