I disagree, this is not what they thought trumps tweets were. It was clear and remains clear in retrospect that trump almost always had control of his own account, if they were trying to emulate that they would be letting alzheimers Joe bang away at his phones keyboard and make typed gafs like he does verbal ones. At the very least they would be trying make it appear as if he had some control over his account, just watching a 5 min interview you can see despite his major confusion he can still form the semblance of sentence that's not a slogan verbatim. The Biden administration tweets are just what every other politician does on twitter, stilted slogans that feel slimy and unnatural. You didn't see it much with Obama so most peoples only exposer to a president's tweets at volume are the bad Orange Mans(the medias need to cover every tweet he made only added to that). In comparison to trump it looks Orwellian, however in comparison to every other out of touch campaign/politician on Twitter it just seems marginally more try hard.
They know Biden is not with it, they know the man's brain is swiss cheese. While he can create a sentence, he can't be expected to -remain- on point for any longer period of time. Allowing him to go ham on Twitter would just be inviting disaster.
Also, Obama didn't do it, and Twitter only -started- existing on the tail end of Bush's term.
As for it being generic political sloganeering comparable to other politicians. No, there are marked differences. Beyond the sheer... volume of it, there is the consistent attempt to sound off the cuff. Now what do I mean by this? Well, normal political sloganeering will use very formal language a more tightly written statement meant to maximize the individual punch through a fairly standard formula. Now look back at Biden's tweet that started this.
This is fairly typical of the normal Biden Administration tweet. The big --- is atypical, but beyond that the tweet is a bit of a mess if it were meant to be the, literally, formulaic sloganeering. The sloganeering section is at the end, the proposal is at the front, its split up, the feel-good section of the proposal is reversed, there are slight grammatical mistakes sewn in, and its way too wordy. Its all wrong. If it were following the formula it'd be.
"Every American deserves access to quality, affordable healthcare. With the Build Back Better Agenda, we're going to expand coverage and lower health care costs by lowering premiums and reducing prescription costs."
The above follows the formula perfectly... but none of these tweets do. They are written in a way to 'sound' more personal, more intimate. Still blatant propaganda, but meant to be closer to spoken word than sloganeering.
Its literally the uncanny valley in text form.
TL;DR: Its not normal sloganeering, it doesn't follow the literal formula for that at all.