because I've seen certain things and the NTSB comment doesn't really make sense, going by the evidence, apart from it being the usual beaurocratic malebovinefaeces you can expect from official bodies until they have looked at things.
There is a stipulated procedure, and if the authorities didn't follow it to the letter it would leave them open to criticism afterwards. Think of the conspiracy theories surrounding recent major events.
I recently discovered that a pathologist doing a post mortem (autopsy) must carry out the complete procedure, even if the cause of death is blatantly obvious.
Of course the blackbox data will confirm any failures (assuming it is intact), but what if they discover that some aspect of an engine had been incorrectly assembled or was metallurgically defective?