I know the Rabbis said that the Second Temple was destroyed because of Sinat Chinam (baseless hatred) between Jews with different opinions, but let’s face it, the presence of the 5th, 10th, 12th & 15th legions under Vespasian & then Titus did not exactly help matters.

#TishaBav

I’ve come to think that what the Rabbis were referring to, though, is the fact the siege was made far easier for the Romans by the behaviour of those conducting the defence, who quite clearly did not unite against a common threat, but indulged in insane infighting

Jews in Jerusalem, 69CE: “We have large enough stores of food to hold out for a number of years.”

Zealots: “You know what would make people fight better? Destroying all the storehouses.”

The revolt should have worked -Rome was in the throes of a full-scale Civil War. It would have been hard to find a more opportune time.
That hope could only have grown when the commander of the Eastern legions left the siege in an ultimately successful bid for the Imperial purple

In the event, not only did that not happen, but the new Emperor & his son became even more invested in Jerusalem’s capitulation; it would present them as successful at maintaining Rome’s Imperium.

The reputation of the Flavian dynasty (which only lasted 27 years) was built on the ruins of the 2nd Temple.

(The eruption of Vesuvius happened a decade after the Siege of Jerusalem. I wonder if the Jews of the period considered it Divine punishment on Rome.)