He's getting paid to shift things to the people that give him money. Like he cares about national parks enough to shrink any of them on his own....but his doners do for more land space without restrictions, that he can allow permits for.
Even if the DOJ was fully staffed it'd only be his loyalists for the most part at this point. Good ol' Kash saw to that I imagine. Man the US is in bad shape when the director of the FBI looks like Aziz from Parks and Rec (no offense to him he was doing a comedy) with his wide eyed look all the time. Yes it's the drugs I know, or at least pretty damn sure about
Lots of assumptions but harder to think of better reasons. Anyone that can tickle Trump's balls (aka give him money) is good to push their agenda.