IMO it isn't much about parasites, it is more a B2B sales tactics turned B2C, and turns out general public likes it. The Project Japan pitch in 1985 was targeting a group of japanese industry experts. It is this group of expert that says the salmon contains parasites hence the customer won't eat it. But in the 90s, after the striking the deal with Nichirei, they find that customer actually like the fatty taste of salmon, parasites wasn't a concern to most.

It's like facebook/tiktok pitching their platform to an HN crowd and we obsess over security, privacy, social bubble, vision and stuff, turns out no one give a damn. People like scrolling on the phone aimlessly. That's the fatty salmon