This is complete nonsense.
The reason we can't navigate the NW passage is due to silt and mud, and nothing to do with the ice.
Amundsen went through there, wrote a book, said it was a terrible experience, thick stinking mud, that would take a whole day to move a boat 30 feet over the mud banks.
hoards of biting insects, took 2 plus years
"Roald Amundsen's expedition through the Northwest Passage from 1903 to 1906 utilized a small, shallow-draft vessel named the Gjøa. The ship's shallow draft was crucial for navigating the narrow and shallow waters of the passage, including areas with sandbanks. Amundsen's choice of a smaller ship allowed him to hug the coast and navigate through waters that larger vessels could not, which was essential for his success in completing the passage"