This could lead to stability instead of a panic. Manipulators should be proud.
It seems that the goal of these walls is indeed to stabilize price, rather than induce selling panic. Evidence: the walls initially appeared when the price started to push 21.00. Once the price fell and started to accelerate down below 20, the walls were pulled allowing the market to recover. The walls reappeared when the price approached 21.00 again with volume.
Conclusion: Big player(s) is(are) comfortable with a current price level and intend to stabilize the price in a 20.00-21.00 corridor for now. They want to avoid extreme volatility resulting from either a short-term bubble or a short-term dump forming from current price level.
I think your conlusion that the wall was put (and removed) in order to stabilize price doesn't hold. It could still have been done to just move the market below (up and down a bit) in order to buy/sell on the resulting swings (induce volatility).
Regarding wanting to stabilize a price at a level someone may be "comfortable" with, David Morgan has this to say:
you cannot manipulate the overall trend of a market.
I think the man is correct. If there really are market conditions to merit a price above $21 then that wall can only be temporary. It might scare the price down for a while and make some people sell lower then they would have. That wall will get eaten or pulled.
