Then read the original article linked in the first paragraph. It's not that they're trying to pretend the documents weren't leaked. It's that systems are all classified to handle information at a given level, and if you find e.g. TS/SCI information on an FOUO system, then you have to investigate it and take corrective action (which often means wiping or even reclassifying the system). So, rather than deal with a huge mess of pointless investigations of classification violations, they're just trying to keep the data entirely off their systems.