They do rust to the hub. For me, the task of breaking them loose fell to the garage (called "Bill's Ineffable Automotive Rehabilitation" of Metuchen, NJ) where the van was initially inspected 3 years ago. They used heat and probably some sledgehammer, and coated the hubs with anit-seize afterwards. There was no problem when I removed the drums for a brake job last November, and used anti-seize again. Current replacement drums from Mopar, and better aftermarket ones, have 8 mm threaded holes for pulling the drums off in case they are stuck. Before installing the drums, make sure you clean all the rust, otherwise they will not sit square.
PB Blaster should help too with breaking the rust, if you give it some time.