PSacremento
Post 1861
609 BCE is not universally accepted as the end of the Assyrian Empire, it is accepted only by some scholars and apostates. Check it out!
607 BCE is based on the Bible and secular evidence, it is also strengthened by the fact that it is a prophetic date, no such claim can be made for the other 'false 'dates. The only thing that is thrown out of whack are the false assumptions of NB chronology whereby there is at least a twenty year gap.
You are somewhat puzzled by the fact that there is the same evidence for 539 BCE as for 587 BCE. Why are you puzzled? Perhaps you fail to understand something. If what you say is correct then why is not 587 regarded by scholars as an Absolute Date as with 539 BCE? That is a question for all the smarts on this board?
The answer to your last question is Methodology.
scholar JW