That's pathetic from Man UTD. The FA should step in. Whether you like them or not, we should not be okay with banning the press because we don't like their stories. And this far more important since UTD are a publicly traded company.
This just like the complaints for a VAR and the refs, it offloading responsibility for what's going on to a 3rd company.
The press and the stories got nothing to do why Man UTD is toxic.
It's something internal because it all the same cycle. New manager then results go to shite and then the negative stories from the press. And note, the negative press comes after the bad results and not prior.
This isn't the way to do it. And internally their message to players should be not to give on iota of what the press says. The press will praise when you're good and turn on you when you're bad. Your job is to perform regardless of what's written about you.