What I'm getting is that far from being a witch hunt, the DoJ have bent over backwards to accommodate him, giving him a ridiculous amount of time to return the documents and he deliberately tried to hide them. Any regular pleb with government clearance found to have squirreled away even one top secret file would have the book thrown at them.
Maybe he just saw them as trophies or his property, but he doesn't appear to have treated them as if they were valuable at all. Although by all accounts he wasn't one for actually reading anything while he was president, so who knows what he was thinking?