Earlier quoted context omitted.
I'm honestly intrigued as to how this is so morally unambiguous. Walmart, any-given-supermarket, Costco, etc., have in-house brands (for example Kirkland with Costco). These became prominent in the 90's and there was similar discussion at the time about the ethics of a supermarket introducing competitors to the brands it stocks. Such controversy has died down and now it is commonplace. Looking at some updated article…
I wouldn’t be mad if they had their own products without using data mining to compete against their sellers. It’s that they use advanced data intelligence to compete. If they competed naively (had a hard wall between their market place division and their consumer products division, I wouldn’t have an issue.
I'd be very interested in what comprehensive reform in that area might look like and unintended consequences that might impact the consumer. I'm a big Trader Joe's fan, and they aggressively push out or white label third party brands. Only brands that are seemingly irreplacable, like Roquefort cheese or single malt Scotch-es, are spared the white label (and even then Trader Joe's constantly puts up 'Trader Joes blue', or 'Trader Joe's scotch' in an endless attempt to replicate). Should it be legal for Trader Joe's to do exactly that, but illegal for them to use sales data to optimize? I'm not sure I'd find that a happy outcome.