Improbable I can accept, even rejection, if it is a considered and honestly held personal view but that still does not make it correct. Similar confirmation bias is exactly the reason the Lagina's are wasting millions drilling an empty hole year after year. Just because someone, or many, believed something before you, does not mean it has to be true. The Norse legends of travelling to the North American continent in approximately 1000 AD were ridiculed by academics until L'aus au Meadows was discovered in the 60's, proved the legends correct and is now a Unesco protected heritage site. What makes anyone so sure that Europeans were not present in Oak Island which is less than 1.000 km south about 200 years later? There was definitive proof on Laus au Meadows that those same Norse travelled or traded with people who had travelled that far South and combining that with the medival
Artefacts discovered in excavations and searches on Oal Island should be enough on its own to at least be open to the possibility.