Having spent the summer of 1982 at Ft. Huachuca, this makes sense. And of course if you go hiking off the beaten path there are the old mines that one can fall into because the boards they may have been covered with a century ago are too rotted to support any weight.
I’ve hiked there in the mid summer. And you can find old mines ANYWHERE in southern Arizona.
If it is just closing the campground because the number of visitors during the summer doesn’t justify the expense of keeping it open, that is fine.