You're assuming Herbalife is a pyramid scheme. To date, there is no definitive proof either way. But at this point, it seems more likely (given the stock price response) that Herbalife is not a pyramid scheme.
So Ackman punished Herbalife shareholders with unnecessary volatility through his actions.
> He’s happy to sell their shares to others. He just wants to do so at a price that’s reduced from now.
You misunderstand how a short sale works. The intention is to buy at a lower price at a later date, not sell at a lower price at a later date.
Yes, the way our financial markets work, speculators on both sides must provide liquidity to the markets. However, presumably the net effect of his short selling (and any synthetic short positions he has acquired) is to reduce the stock price, thus reducing profits of Herbalife executives and those who have helped Herbalife raise operating capital by investing in the company in the past.
Now, if your contention (edit: "contention is") that selling Herbalife at a low price is an amoral act, that doesn't necessarily mean the converse (buying at a low price) is a moral act. I'm just saying your argument begins with a false premise: that his intention is to sell Herbalife shares at prices below current market price.
Also, it's possible for an action to be amoral and its opposite to simultaneously be amoral, but that's a difficult argument to construct well in general. Having argued that it's amoral for him to sell at a lower price in the future, it's difficult to construct an argument that it's amoral for him to buy at a lower price in the future without contradicting your earlier arguments.
