The idea that the Coast Salish and other Northwest Native Americans cultivated plants was disputed until relatively recently. Famed anthropologist Franz Boas and his disciples argued that Native Americans didn't need to cultivate plants thanks to abundant salmon runs; they could subsist on wild forage instead.
According to Doug Deur, an anthropologist at Portland State University, Boas disregarded ample evidence to the contrary. He thought he was being benevolent: The idea that people who were predominantly hunter-gatherers could have a culture as rich and complicated as that of the Coast Salish stood in radical opposition to more Eurocentric theories of cultural evolution. These held that hunter-gatherers were by definition savage, and therefore were improved when forced to convert to European technologies and living standards.
But there were consequences to such willful blindness. Native Americans who later tried -- and continue to try -- to make land claims based on old family agricultural plots were denied. What use did fisher-folk have for land, anyway?