This was a shockingly dumb move. Whether or not you think these actions were politically motivated or made in good faith, it just poured liquid oxygen on the "reform section 230" fire you're seeing from both sides of the aisle - one using the censorship reason, the other using the disinformation reason. There's no way you don't block a newspaper, and the press secretary, and prevent anyone from even private messaging…
I agree they blundered here. They don't want to be hijacked by another "leaks" story days before the election but now the suppression of this has become the entire story, and its convinced a lot of people the story is true and dangerous to Biden. Even if the email is true I don't see how its dangerous and if the only media carrying the story are the NY Post and Fox it doesn't hurt Biden.
If they had just left it alone, maybe attached the standard "this might be false" disclaimer, it would likely have passed as yet another partisan thing, but now they've gone and infused it with a bunch of power it didn't have prior.