I think JANMCN that your source is a bit mixed up. I have spent some time researching various sites including legal sites to square what has me confused.
I did not know it, BUT there are, in fact, TWO different kinds of executive privilege. PRESIDENTIAL COMMUNICATIONS and then DELIBERATIVE PROCESS.
The first has to do with as it says The President and then of course the site you linked is correct in that you cannot get wiretaps and/or grand jury information without a lot of grief.
The second type AND THAT IS WHAT HOLDER IS CLAIMING, refers to the actual process and Holder has made it clear that it has to do with how to handle this particular hearing. The items in questions are emails and the like referring to how to handle this hearing. That makes a bit more sense to me since all I have heard and read is that it specifically had to do with the original claims that NOBODY in the administration knew anything and then when really pressed...I think 20 minutes before the last session....they took it back but refused to allow anyone to see WHY DID THEY TAKE IT BACK.
I certainly would not claim to be a lawyer and surely would not take anything that anyone says as fact until it is fact but this makes sense and sort of aligns with the reports on MSM.
A few links if you want...I really worked hard to disprove the sarcasm from JANMCN in your last note to prove I can work a computer...and actually one of them is from the original link given
Obama shielding DOJ from scrutiny - Right Turn - The Washington Post
The facts behind Obama’s ‘Fast and Furious’ executive privilege claim | The Raw Story
Executive privilege claim unwarranted | HamptonRoads.com | PilotOnline.com
News from The Associated Press