Quite the box they're in there.
Let me throw occam's razor out there -- unless Bezos and/or Amazon PR people leaned on the WaPo to write this story, then it's exactly what it looks like, a random writer with a critical thought piece about Amazon.
If you've got evidence of Washington Post writers trampling their journalistic credentials and planting favorable stories for Bezos you should share that along with your accusations otherwise you should maybe hedge your claims a bit. Eh? Maybe go look up the authors for these pieces on twitter, they're often there, and just go ahead and accuse them right there where they can see it. Such a shameful thing to do in my opinion, and so far fetched.
When someone comes up with a profitable model that can support real, independent journalism, perhaps we can start making that argument. Personally, if I compare quality journalism with a blind spot for Bezos, neo-nazi/alt-right crackpot "news" sites and small-town Romanians making up fake news to go viral on Facebook, I'm inclined to think that what little bias WaPo has isn't really that big of a problem.
I don't think we should assume the worst and discount anything WaPo says (or doesn't say) about Amazon, but I think it's important to keep in mind that Bezos owns the paper, and just continue to think critically about things.
The simplest view is that Bezos owns WaPo and therefore he will have undue influence over WaPo.
I don't ever envision WaPo going on a anti-Bezo rant like they do with Trump/et al.
Also, occam's razor says Bezos bought WaPo for his own benefit. Nothing wrong with it. But people are so eager to tech gurus the benefit of the doubt or project some "saintly" traits to them.
Ok back to the subject.
It took me a while to put to words what I find objectionable about your view -- it's intellectual laziness masquerading as critical opinion.
Rather than grappling with a tough problem, it advocates abandoning the problem completely into some sort of post truth fluff, then dresses that up to pose as wisdom.
There's no critical analysis of how bias manifests or the tradeoffs of that bias versus other biases that might be introduced by other sets of circumstances -- there's no meat to that line of thinking.
It's intellectual high-fructose corn syrup.
The substance itself, if you look closely, is only yet another layer of appearance, slightly closer to the Truth - God.
So FAIR is a biased news source, and we should disregard any criticism they present about any media companies. See how easy this is? Didn't even have to think, which I suppose is the appeal.
You've got bigger problems if you're forming opinions about Amazon based on the relative frequency of positive vs. negative headlines in the news(a metric which is literally the article's concern). Safeguarding the integrity of input sources is only a hugely important problem if you also outsource thinking and evaluating arguments to them.
"This reverse submarine -- a critique of Amazon published by Jeff Bezos' paper -- tries to give what appears to be a biased news source a patina of unbiased objectivity by running what appears to be a piece that's critical of the thing it's thought to be biased toward."
https://news.ycombinator.com/item?id=14877216#14878179
Whether this is true or not actually does not matter as long as the conflict of interest is there.