Ok then, I'll bite: If can agree that 99% is "true" (names, dates, events, fibers, squiggles on rocks, U's, logs, strange lights, etc...), and that 1% is false (the supposed treasure part), then :
What are we talking about ? If you acknowledge there's no proof of treasure (the 1% of the proof), then ....... what are we all here talking about ? Why does anyone care about "fibers" ? "uncanny out of place squiggles" ? etc... ? Heck, I can walk out my own front door, and ... within a mile of my house, find every single thing that's talked about in this legend. Ok, so what ? If we can all agree that they don't necessarily mean "treasure", then : What are we talking about ?
Maybe by studying the story(which you are conceding as 99% true), we can determine what exactly went on there. I can't recall anywhere in the world or in recorded history, that something like OI happened before.
Is this treasure? A burial vault? A sink hole? An alien base? An elaborate water system? The Templars personal smoker? The resting place of such powerful old world objects that have been hidden from mankind? A mistake?
To write it off as a most probable is a dis-service.
I was a guard at a bank this actually happened to me:
A guy walks into a bank with a ski-mask on and a shotgun in his hand. What do you think his most probable intentions were?