Because the way in which Jesus' biography is crafted to fit some of those requirements is very suspicious.
-Must be born in Bethlehem... but Jesus was from Nazareth. Ah, but through a strange quirk of fate, his heavily pregnant mother was compelled to travel almost 80 miles to take part in a census. There is no record in Josephus of a census, and even if there was, this isn't generally how they are conducted, and even if they were, one does not drag a pregnant woman across the country. And even if you did, why would the Romans conduct such a matter in Bethlehem and not Jerusalem? This is very suspicious.
-Cannot be descended from Solomon. Joseph was descended from Solomon... this is undoubtedly why Jesus claimed Joseph was not his real father. It would have disqualified him. Given the propensity for Greek and Roman heroes to be descended from gods, it was probably not as crazy sounding then. Just a way to avoid being declared ineligible for the position.
-Being born of a virgin wasn't one of the requirements. That "born of a virgin and called Emmanuel" (which Jesus was not called) was a sign of something else entirely.
All the rest of the so-called parallels are cherry-picked and after the fact. Things no Jew would recognize.
I could argue all these prophecies, just as others have here, but it wouldn't convince you regardless of the evidence given, at least it appears so at this time..... I say this because you are approaching Jesus from the position that Jesus was NOT accepted as the Messiah by the Jews rather than ask what was it that convinced the Jews He was the Messiah.
I do, however, find it interesting you're referencing Josephus as I understood you were not open to anything for reference outside and only the KJ version of the Bible. What's changed. (???)..... Am saying this since you'll look toward an historian, subject to his own leanings, yet you argue that the NT authors, many who actually lived and walked with Jesus, are somehow less reliable....It would certainly be logical to place more significance on those who were actually with Him.
But let me say that one doesn't have ‘to fit’ Jewish requirements to the Biography/Prophecies of Jesus. (Though this is a standard argument Jews are often taught)..... The Christian understanding from the Old Testament, 'when compared' with the details of Jesus’ words and actions (as recorded by the Jewish followers and writers of the New Testament), is a very reasonable one,.... and is actually a 'better' one than Jewish explanations of the relationship between the Suffering/Rejected messianic figure and the Victorious/Acclaimed messianic figure.....It wasn't just a Victorious Messiah Jews were seeking, the Jewish Leadership also understood He would suffer and be rejected.
Just as the OT taught and as Jewish teaching recognized identifying the Messiah was, and is still today, dependent on Israel changing her mind about Jesus, about truth, and about social justice. All which Jesus taught during His ministry....to the crowds...to the diciples...and to the individuals.