The differences in tow ratings you are seeing are the 4 cyl. vs. 6 cyl. and 3.21 gears vs. 3.73 gears.
A 6 cyl 3.73 geared TJ will pull up to 2000 lbs. according to specs. Also note the tongue weight max of 200 lbs. Recommendation is to either plan on long breaking distances or have supplemental braking. And don't expect to maintain speed going up a long hill. When packing, watch your GVWR - passengers, stuff, and tongue weight add up fast and typically there is less than 1K lb. to play with before the lift kit, the tires, the winch, the custom bumper...
Ex owner of a TJ and current owner of a JK.