His complaints don't hold merit because he entered into a binding agreement to buy Twitter after waiving due diligence rights. Zatko was fired in January. Musk had and waived his chance to discover these things. It's too late now.
Pop legal quiz - does "waving due diligence rights" during an acquisition remove the other party's liability for fraud they've committed against the prospective buyer?
What fraud though?
If Mudge's allegations are true that Twitter has been defrauding the public in their reporting, failing to abide by the terms of a federal consent decree, and generally turning a blind eye to real problems to prop up their image, then "waived due diligence" or not, Musk has an out from the acquisition, and cause for a significant tort claim.
Musk literally tweeted about the « bot problem » on Twitter before the acquisition.