It's got axle wrap for sure. Both sides have traction evenly so other then the leafs springing back and forth, it's not beating it up too bad. If he was open, he'd probably break the spider gears but he's got a truetrac. He's also for alloy axle shafts so the splines are much stronger. Honestly though, the axle wrap is probably helping him not break anything.
The problem with those tube bumpers is that they don't mount directly to the crossmember. Typically you have three sets of holes on the bumper and two on the bracket. This allows you to have the bumper mounted 1" lower so you can clear your rear tire. Problem is if there is any leverage on the bumper the offset will allow the bumper to ply itself off the rear crossmember, in either pulling or getting rear-ended. I've had two of those bumpers and and no bumperless till I find something more suitable.