The 70 years does NOT apply to Jerusalem and the temple. The 70 years applies to Babylon and is the length of time it would be the dominant world power. You can see this clearly in the prophecy of Jeremiah where he discusses how all the nations (plural) in that region would be dominated by Babylon:
“Therefore this is what Jehovah of armies has said, ‘“For the reason that YOU did not obey my words, here I am sending and I will take all the families of the north,” is the utterance of Jehovah, “even [sending] to Neb·u·chad·rez´zar the king of Babylon, my servant, and I will bring them against this land and against its inhabitants and against all these nations round about; and I will devote them to destruction and make them an object of astonishment and something to whistle at and places devastated to time indefinite. And I will destroy out of them the sound of exultation and the sound of rejoicing, the voice of the bridegroom and the voice of the bride, the sound of the hand mill and the light of the lamp. And all this land must become a devastated place, an object of astonishment, and these nations will have to serve the king of Babylon seventy years.”’ - Jeremiah 25: 8-11
Furthermore, even the Society confirms this in their own writings! --
“Isaiah goes on to prophesy: "It must occur in that day that Tyre must be forgotten seventy years, the same as the days of one king." (Isaiah 23:15a ) Following the destruction of the mainland city by the Babylonians, the island-city of Tyre will "be forgotten." True to the prophecy, for the duration of "one king"—the Babylonian Empire—the island-city of Tyre will not be an important financial power. Jehovah, through Jeremiah, includes Tyre among the nations that will be singled out to drink the wine of His rage. He says: "These nations will have to serve the king of Babylon seventy years." (Jeremiah 25:8-17, 22, 27) True, the island-city of Tyre is not subject to Babylon for a full 70 years, since the Babylonian Empire falls in 539 B.C.E. Evidently, the 70 years represents the period of Babylonia’s greatest domination—when the Babylonian royal dynasty boasts of having lifted its throne even above "the stars of God." (Isaiah 14:13) Different nations come under that domination at different times. But at the end of 70 years, that domination will crumble.” – Isaiah’s Prophecy I, p. 253
The bible and the secular records match. The twisting of logic and scripture originates with the Society's need to maintain this flawed chronology that was developed in the 1820's. Without 607 BCE, 1914 falls as does their 1919 date of appointment as the "faithful and discreet slave". The entire authority of the organization hangs on the thread of 607 BCE.