803.04 Stance, Subsequent to Teeing Off
D. A player must choose the stance that will result in the least movement of any part of any obstacle that is a permanent or integral part of the course.
If you are bending branches to take your stance you are violating this rule.
Lets say you are under a bush. You can't bend the branches of the bush back to take your stance. You have to get down, slide a foot in and try to minimize movement. This includes movement from the natural position of the branch.
I think you are interpreting things differently. I have spent many a day in an awkward, one knee, almost on my side stance to try to avoid bending branches from their natural position. To do otherwise would require me to move them, which is against the rules.
You can't hold back the branches with your back.
Quote the whole thing, not parts.
A. Obstacles to a Stance or Throwing Motion: Players must choose a stance which results in the least movement of any part of any obstacle except as allowed for casual obstacles by 803.05 C. No relief is granted from park equipment (such as signs, trash cans, picnic tables, etc.) as they are considered part of the course. Once a legal stance is taken, a player may not move an obstacle (or hold it back or bend it) in order to make room for a throwing motion. It is legal for a player's throwing motion to make incidental movement of an obstacle.
Therefore, a legal stance is made. It does not state what stance, it states it has to be a legal stance. Once I take my stance, I cannot move the obstacles behind me any farther. Anything moved within that legal stance (branches against back) wold be considered under least movement. If I leaned back farther to press them, it would be illegal. The rule allows for you to get into a legal stance, it does not say you have to do any sort of yoga trick possible to get your foot in there without moving branches. I for one, am limber so I can do this. How would a grandmasters tournament look? I bet those old guys aren't sprawling all over the place to reach a lie.