There are several reasons, the primary or routine one is,,,
I believe it stems from laziness. Most scribblers out there seem to wait for an article to come out from an “approved” source, and then they parrot it, without ever being the least bit skeptical about it. They dont run into any risk of being wrong because, “Everyone else thought that too.” And they are rewarded with the affirmation of their peers. All while doing the least amount of work possible.
The less frequent reason is self inflicted by the Phins, Media folks take the easy road when the team, or a member does something stupid that the media people know it’s safe to criticize, “Bullygate” Tyreeks weekly episode in Law enforcement interactions, or on something safe because “The entire league condemn’s it.” ie the tampering stories. The entire league may well be guilty of doing it, but,,,,, “We all hate Miami anyway/” is the predominant feeling, so condemning it is again “safe”.
It’s the same everywhere in media, the same stories, often using quotes from each other with little to no skepticism.