Like most news, they want to control the narrative. As they drip it out, they want you to form a specific opinion. Psychology has shown first impressions can be nearly impossible to change, especially if they conform to your already held beliefs.
There's only one plausible reason. It's because they don't actual tell the narrative that Musk and other right-wing conspiracy theorists are suggesting they do.
Jack Dorsey confirmed as much and advocated for releasing them all immediately without editing them.
Musk doesn't care about a legal review of the documents, at least according to him when he fired their legal counsel over it.
Because the whole purpose of the exercise is to manufacture right-wing agitprop, not an actual good-faith effort to provide transparency to the public?