And those of us who are riding pedal assist-only e-bikes at 5-15mph on the motorized trails will be maimed or killed by Jeeps and motorcycles coming around blind curves and hills at higher speeds than we can realistically attain.
The 20mph limit on a 250 watt middrive can't really be attained climbing on steep terrain by a heavy rider, even at full assist. The only ones that might be safe will be the 4500 watt 40mph eBikes (more like e-cycles).
I've been riding in Moab since the 80's, in those days, the only places to ride were all roads and trails open to motorcycles and jeeps, and even then on those fully rigid and basically crappy bikes compared to what are available now, we were faster than jeeps almost everywhere. These days, it's rare to see jeeps or motorcycles on the trails, it's mostly side by sides and even those are slower than bicycles except on smooth dirt roads. There's plenty of fantastic riding there for ebikes, and you won't get run over, you should go try it out.