Short selling unearths fraud. Check out some of the shorts Muddy Waters had against fraudulent Chinese companies, or the short positions against Wirecard. The latter was a complete fraud aided by German regulators and finally taken down by shortsellers and the Financial Times.
A great book on a specific example is David Einhorn in "Fooling Some of the People All of the Time". He routinely finds fraud and shorts them, in this case, Allied Capital.
