'scholar':
Babylon's time as a World Power ended with its overthrow in 539 BCE by the Medo-Persian Empire. However, the 70 years of Jewish Exile and servitude to Babylon did not end until 537 BCE when Cyrus released the Jewish captives.
In the poor addled mind of 'scholar' (and other JW cronies), the Jews arrived in Judea, marking the end of 70 years. But the problem (actually one of a great number of problems), is that directly contradicts Jeremiah 29:10. They make a big deal about their faulty translation saying "at Babylon" in the first half of the verse, but quietly ignore the second part of the same verse. In the JW interpretation, the Jews arrive in Judea, and then attention is given to their return. Once they're already there. It's as dumb as it sounds.