Have you noticed that when the WT and the non-JW churches write (and talk) about the destruction of Jerusalem they do so in regards to the year 70 CE, but not also in regards to the year 135 (or 136) CE? I think they rarely (if ever) mention the latter one, since it would complicate their explanation of Matthew 24:1-35 and of its supposed fulfillment of the generation of Jews from Jesus' days that would see the destruction of Jerusalem. The fact is that the destruction in 135 CE was far more devastating for the Jews in Judea than the one in 70 CE, yet most Christians probably don't even know about the latter one. The tribulation of 135 (or 136) CE was a far greater tribulation than the one of 70 CE! It was after the end of the war in 135 CE that the Roman emperor named Judea as Palestine (namely "Syria Palestina", in honor of the Philistines, the historical arch enemies of the Jews) and banned Jews from entering Jerusalem (except for once a year).
https://en.wikipedia.org/wiki/Bar_Kokhba_revolt says the following.
'In 132, the revolt led by Bar Kokhba quickly spread from central Judea across the country, cutting off the Roman garrison in Aelia Capitolina (Jerusalem). ... Despite arrival of significant Roman reinforcements from Syria, Egypt, and Arabia, initial rebel victories over the Romans established an independent state over most parts of Judea Province for over three years, as Simon bar Kokhba took the title of Nasi ("head of state"). As well as leading the revolt, he was regarded by many Jews as the Messiah, who would restore their national independence.
... The Bar Kokhba revolt resulted in the extensive depopulation of Judean communities, more so than during the First Jewish–Roman War of 70 CE. ... The Jewish communities of Judea were devastated to an extent which some scholars describe as a genocide. However, the Jewish population remained strong in other parts of Palestine, thriving in Galilee, Golan, Bet Shean Valley, and the eastern, southern, and western edges of Judea. ... In an attempt to erase any memory of Judea or Ancient Israel, Emperor Hadrian wiped the name off the map and replaced it with Syria Palaestina. However, there is only circumstantial evidence linking Hadrian with the name change and the precise date is not certain. The common view is that the name change was intended to "sever the connection of the Jews to their historical homeland"; a few scholars dispute this.
The Bar Kokhba revolt greatly influenced the course of Jewish history and the philosophy of the Jewish religion. Despite easing the persecution of Jews following Hadrian's death in 138 CE, the Romans barred Jews from Jerusalem, except for attendance in Tisha B'Av. Jewish messianism was abstracted and spiritualized, and rabbinical political thought became deeply cautious and conservative. The Talmud, for instance, refers to Bar Kokhba as "Ben-Kusiba", a derogatory term used to indicate that he was a false Messiah. It was also among the key events to differentiate Christianity as a religion distinct from Judaism. Although Jewish Christians regarded Jesus as the Messiah and did not support Bar Kokhba, they were barred from Jerusalem along with the other Jews.
Modern historians view the Bar Kokhba Revolt as having decisive historic importance. They note that, unlike the aftermath of the First Jewish–Roman War chronicled by Josephus, the Jewish population of Judea was devastated after the Bar Kokhba Revolt, being killed, exiled, or sold into slavery, with so many captives auctioned at "Hadrian's Market" that the price of the Jews were as low as the price of a horse. Jewish religious and political authority was suppressed far more brutally than before. The Jews suffered a serious blow in Jerusalem and its environs in Judea, but the Jewish communities thrived in the remaining regions of Palestine—e.g., Galilee, Bet Shean, Caesarea, Golan and along the edges of Judea. Captives that were not sold as slaves were deported to Gaza, Egypt and elsewhere, greatly adding to the Jewish diaspora. ...
Judea would not be a center of Jewish religious, cultural, or political life again until the modern era, although Jews continued to sporadically populate it and important religious developments still took place there. ...'
waton, your reference to verse 21 in support of your claim is a good point.