You just bring a different perspective but always there are some traders who will be buying and selling at each and every price levels because of their technical and fundamental analysis. Even people who are following same kind of strategies, due to different time frame they are following they will get into/exit from at different price levels regardless of they are using same strategies.
Yeah OP's concern must be an unique one but if there were no sellers in-between price levels then we might have tested some big levels by this time; I am seeing those shorters as a hurdles in the passage of price movements. I agree they are the liquidate providers but without them also we might have reached where we have bitcoin today but most people might have not got chances to buy bitcoins cheaper than they entered in-between price levels.
Probably people who entered (like microstrategy who started buying bitcoins after 10k price levels) lately still got enough volume they wanted, might need to thank those liquidate providers as per OP's view.