Even if it were possible for the BoM to be anything but a 19th century fabrication, just supposing there's a universe where it's true, it still wouldn't be a reason to embrace Mormonism. There are just too many negatives about the culture to make it worth it.
I don't know why BYU doesn't disavow this kind of apologetics. It just makes them look weird. Oh yeah, their customer base.
Also, in the video, the guy admits that the area was already mapped out in the 18th century (1700's).
Therefore, that information was available to Joseph Smith as he began his work of fiction called the BoM, that he later tried to sell to the Canadians.
No doubt that JS pulled from several different sources when putting together the BoM.
If I was him, I would use every resource, and do proper research so I wouldn't look completely like a fraud.
I've been persuaded the "Multiple BOM Authors Theory" is probably true. Here's Part I of Craig Criddle's presentation at the 2009 Exmormon Conference. Craig's "discovery" of strong evidence linking Parley P. Pratt to the "production" is noteworthy.
Cabdriver Confession: I need to watch this one; I was slammed at the 2009 Conference, and I have watched Charles M. Larson's video from the same time. I have corresponded with Craig, and he is one of those authentic jewels we are privileged to meet in our journey out of Mormonism.
The additional segments of the video are linked on the right.