It's the buyer's responsibility to undergo due diligence before making serious, legally-binding offers. Musk is very clearly scraping for excuses now that he has buyer's remorse.
That's what I think he's actually trying to do, as part of his "master plan part III". Twitter is only valuable because of users - but they are not worth this incredible premium. He's seen how attempts at launching 'free speech' platforms have gone.
He can easily build a competitor for a fraction of the deal's price. He can easily outspend any company. But that doesn't guarantee users - eyeball time is a limited resource. However, if he torpedoes twitter, he can get a bunch of users from the wreckage.
And, you know, profit from some nice pump and dump in the meantime.
To adapt an adage - Musk has already established what the company is, now he's just negotiating the price.
Pretty sure users would notice if 1/3 of all tweets are computer-generated.
What if there's internal data indicating that it's closer to, like, 30%?
In that case, a buyout offer conditional on a DAU audit is certain to expose that data, and that's checkmate for TWTR.
Musk can then either buy it at a massive discount, or use the enormous amount of free press to launch a competitor with mandatory device attestation.