The snubber only helps exact balanced forward motion . It's a seesaw lol . Even cars going in a straight line one side is pushing down and one lifting up.
Yes the wheels are unevenly loaded. When the snubber strikes the floor pan, the weight transfer of the vehicle ceases to compress the rear suspension and the weight is then transmitted directly to the axle thru the snubber. This increases traction dramatically. Think equal and opposite reaction.
The imbalance in the loading at the tires is ONLY addressed by the springs. If you could disconnect the springs and somehow launch, the body would just pivot around a bottomed out snubber.
This is precisely why the mp super stock springs are heavier on one side.