TBH, that's actually what I don't understand.
I mean, sure, those guys made a lot BS up, like every religion did. Even the historiography of the ancients was more propaganda than what we'd call a honest scholarly approach nowadays. The Jews are no different in that aspect.
And, sure, they tried to make themselves more ancient than they really were. Most civilizations tried to stretch their history all the way to the creation of the Earth. Check out the lists of kings of Kish for some guys who clearly went "ah, screw it" past a point and started padding with ridiculously long lifespans as they went back. And I mean even after factoring in the conversion factor screw-up that made them look even more ridiculous, things still get silly as they get farther and farther back and still have a few thousand years left to pad.
Again, the Jews turn out to be just
people in that aspect. Their kings and priests pad things in their favour, and sometimes lay the BS so thick, it's ridiculous.
And their moralizing stories are at times like they're not even trying to pretend it isn't fiction. I mean, you have stories where there was an orchard owner called Fruits, and he runs into trouble with queen Slut, or where a jewish girl called Jewess (yeah, that's what Judith means) tricks the enemy commander. It's not like they even bothered finding believable names for their characters, you know?
Heck, even their genesis story, has a first man called Man. Or sorta like calling him Homo nowadays. Yeah, Adammu already meant "man" by the time of Ebla.
And generally, we know that most of them didn't come from anywhere and as a separate group they aren't as ancient as they thought either.
But why would anyone try to erase them from history entirely?
And, at that, what's with the idea that they were making those stories up for the
Romans? The thing is, the Romans had very rigid views of honour and duty and all that. Even Odysseus was a
villain by Roman standards: just about every time he does something clever by Greek standards, it's despicably dishonourable by Roman standards. So, really, if a bunch of Jews were actually to come up with a fake history to con the Romans with... they couldn't come up with better stuff than
that? Most stuff in there is stuff that you'd want hidden from the Romans, not stuff you'd invent to make the Romans like you.
I mean, really, the kind of thing that Romans respected the heck out of, was a last fight to the last man or honourable suicide like at Masada. That's the kind of story you'd want to invent if you want the Romans to respect you. Stuff where a civilian girl called Jewess dishonourably tricks and kills the enemy commander is exactly the stuff you wouldn't want to brag to the Romans about. Or stuff like telling the troops before an assault that the enemy's gold is tainted and it should all be given to the priests for decontamination? (Yeah, I guess those priests of Yahweh doubled as a hazmat team

) Yeah, screwing your soldiers out of a fair reward is exactly what the Romans would appreciate... NOT.