What's the Moral Argument Against Shorting Stock?

The NYT featured an extraordinary comment by a Merrill Lynch strategist in an article on how the wealthy are often able to make money in a period of market volatility:

"There seems to be a moral argument against shorting, but from a purely practical point of view it leaves (hedge funds) in a better position to manage volatility."

It would have been interesting to know what the moral argument is against shorting. When an investor shorts a stock they are betting that it is over-valued, just a...