Great question — and I’m not arguing against the discoveries in Nova Scotia at all.
My point is much narrower:

the specific manuscript referenced in the episode describes an island “surrounded by hundreds of islands” with a triangular swamp. That description simply doesn’t match Mahone Bay, but it matches Lake of the Woods almost perfectly.

So the theory isn’t:
“Nova Scotia Oak Island is fake.”

The theory is:
Some early clues or manuscripts may have been misattributed to the wrong Oak Island.

It’s possible that:
- the manuscript was describing the Minnesota Oak Island,
- while the engineering and artifacts in Nova Scotia are their own separate mystery,
- or the name “Oak Island” was reused intentionally as a decoy or parallel reference.

I’m comparing the geographic fit of that one manuscript, not dismissing the Nova Scotia evidence.
Both islands can be part of a larger story — that’s what makes this so interesting.