Aside from the question of the authenticity of the quotes above, Josephus does give a very vivid and accurate description of the destruction of Jerusalem that seems to confirm the prophetic words of Jesus about the destruction of this city.
Of course, critics like good lawyers can always question anything and everything on any subject. But one always has to investigate the motivation of these critics before accepting their words.
We have very few windows to the past except these ancient historians. The other window that has opened up for us in modern times is the archeological one that has brought new understanding ...and, in some cases, confirmation of the Biblical record.