That makes no sense for Michigan at all. I’d imagine Michigan land use is mostly forest (so much national forest/protected wetlands here), then agriculture, then urban space (Metro Detroit is most of this), then a little pasture. The only way “idle” makes sense to me is if any protected forest/natural land is considered “idle”
I know this map isn’t clearly broken down by state, which is (part of) why this map struggles to communicate what it’s trying to say IMO. I think the first map in the linked Bloomberg article (with land use data broken down on a more granular level) does a better job at communicating the same trends