Important line from the article > a practice at odds with the company’s stated policies... > .. as stated to congress
You want to start a discussion about company stated policies and how each person feels they do or do not live up to them? That could go on for quite awhile! edit: it was mostly a joke, calm down.
In speaking with Congress, they're stating to everyone that they are there to act as a platform for third parties. They're a "pass-thru" service.
That implies that while metadata may be being collected, you shouldn't be looking at it, as it isn't "yours". It would be like a cloud provider going into business undercutting their client's because they weren't savvy enough to encrypt their business records. Or the post office going through your B2B mailings, figuring out your footprint, them becoming a competitor.
You have one job. That's it. Once you start abusing your access to your seller's transaction data to figure out where to or whether to diversify into their vertical, there is a fundamental breach of trust, and a very reasonable case to be made in having exploited something you shouldn't be.
That's the Hobbesian Leviathan for you; you don't need all those little businesses anyway!