I'm aware of the indigenous-proposed cull of pinnipeds on the west coast, and I would say that there are very divergent opinions on the issue in first nations. They're not a monolith.
I think science probably has a bit of an advantage over the more on-the-ground and on-the-water information in that the pinniped diet is so varied. They prey on so many different species. It varies by location, season, age and sex. Having comprehensive diet-sampling studies, for me, is more relevant than someone observing a seal feeding on a certain thing.
The other thing is that pinnipeds are very in-your-face kinds of predators. We don't see other predatory fish feeding on salmon, cod or herring, but we can see seals. I think that's why they often end up as a scapegoat for the natural mortality of fish.