The practice of short selling stocks provides an adverse affect on companies who's stock is being manipulated. CEOs believe that their first loyalty is to investors, not realizing that mayority of investors are in for short term profits. This type of market manipulation jeopardizes the employees of wall street companies, since now the CEO is compelled to drive the stock price up, thus reducing workforce to do so.
By making short selling illegal you will encourage the practice of long term investment, force the wall street consumer to place their money in companies that provide dividends, and eliminate the "hit & run" CEO who looks only for short term profits at the expense of the employee.