Everyone moving large amounts of money around has something to hide.  It's much better for the security of their clients and security of their own employees to keep things somewhat obfuscated.  I could see CoinJoin making it easier for a Madoff to cheat his investors, but as we know there's nothing preventing a another Madoff from cheating his clients using currently available financial tools to hide fiat transactions.

There may be an opportunity for someone to in the finance industry to abuse CoinJoin, but I'm not a fan of punishing the masses due to the abuses of the few.

As n0nce alluded, privacy is a human right, and legally speaking corporations have been declared to have similar rights being that they are a congregation of people conducting business as a common entity.