It's passive-aggressive health advice. She sets herself up as an authority and then gives a perspective. She also has language like this: "If, like my friends

It's passive-aggressive health advice. She sets herself up as an authority and then gives a perspective. She also has language like this: "If, like my friends and family, you choose to continue to eat seafood, I would urge you to at least start asking questions." So "asking questions" is the "least" you can do, she may have a veneer of politeness but her opinion on what people should do is clear. Further evidence is the flow of her arguments. She starts off talking about the mislabeling of fish, but then says "Let’s say you buy your seafood from a store that correctly labels its fish, or from a fisherman you trust. Maybe you even catch it yourself. But no matter how careful you are..." and then dives into the microplastics. So even if you are able to bypass her argument about mislabeling, which is filled with a lot of maybes in and of itself, in her opinion you still shouldn't eat fish because plastic. Yeah, this is the health advice equivalent of "no offense, but... insert offensive thing"