Yes, which was why my original comment distinguished between the right to bar shipping and the right to economically exploit.
Even if Canada prevails on ownership of every single Arctic island, a passage more than 24nm wide would mean supertankers could come through, and Canada would not be able to forbid it.
That's a claim which, from looking at a map, is unlikely to hold up; internal waters are lakes, rivers, and inlets which come further in than the baseline established by the coast.
The only exception I can find is for nations which are made up of an archipelago of islands, and Canada is not one. So again, so long as there's a wide enough route through the islands, it doesn't matter what country owns the islands -- the sea passage between them would be open to international shipping.
Just looking on google maps now, there is a chokepoint across the passage that has several islands - this makes a contiguous territorial water zone (as each island is within 20 google-map-miles), if Canada's claim to ownership of the islands is respected. I assume this is why the argument is on ownership of the islands rather than route of the path.
Even if Canada prevails on ownership of every single Arctic island, a passage more than 24nm wide would mean supertankers could come through, and Canada would not be able to forbid it.