A story can be interesting and relevant but impossible to prove, and you can still report it honestly by simply making it clear what came from an anonymous source and what is verifiable fact. But it's very easy (and appears to have happened all over the place in this particular article) to cite what someone tells you as fact without making it clear you're just reporting what somebody said.

In fact, the article in a couple of places appends "sources say" at the end of some statement, making you think you're reading a fact until you've reached the end of the sentence. Which IMHO is a "journalism anti-pattern".