A blow, and I'm not sure I agree with the judge that the defense shouldn't see the MFT or whatever (did it really expose means or other protected methods - I don't knwo). However, to call a guy who would be testifying on a forensic investigation of a computer and alleging the FBI or whoever messed up the forensic investigation and who has never testified in this field or otherwise qualified himself in that way was dicey at best.
Example: I'm a pilot. I can testify to lots of things about flying and how small aircraft work. And I might be able to tell why a plane crashed, if the cause were simple enough and the evidence obvious. I'm not an expert though in investigating crashes and certainly am not an expert in questioning the NTSB's methods.
Granted, that's not a close analogy, but I think most of these decisions are at the superficial level in this case and no actor in the case is arguing in technical terms very well.