the reason I was given (back when i first started off roading) was you could bend/ chip/ damage a ring gear. I don't know if this was specific to the late model TJ axles, but it had something to do with the way the gears were cut. They weren't as strong when you were loading them up with extra forces in Reverse.I’ve seen this before. Why?
The only practical reason I can think of is safety related; if something breaks while pulling in reverse it would fly straight toward you front m in front through the front windshield vs pulling while in forward gear a component would fly toward you from behind, less likely to strike the driver. Is there another reason?