Kinda leads one to wonder what exactly they think "isn't in the public interest" and what they are hiding. Is there something in the requests that they believe is against the public interest? Perhaps that will erode faith in the government? Or is this just bullshit?
If it was just something small, they'd probably just redact it out. If it isn't them just being dicks...then maybe it actually has to do with things they have no legitimate reason to redact, like people's opinions. Maybe people freaking out about things?