> I think it's misleading to present it as a legitimate action
Legitimate or not, the policy is what's there now, until challenged. You agree with that:
> might attempt to enforce it and courts might uphold that enforcement
And, clearly, so do their lawyers.
The problem is that the policy will not be challenged if people accept it as legitimate. Talk shows aren't common enough or important enough that a challenge is guaranteed to come. And so the ratchet of authoritarian takeover advances a little bit further, as Donald Trump works towards his quite explicit goal of making it illegal for the media to say bad things about him.