They are used to getting away with stuff. Bloomberg comments on LIBOR:
We don’t countenance bank bashing. Nor have we ever called on regulators to bust up big banks. But it’s difficult to defend an industry that defrauds the market with fake interest-rate figures, thereby stealing from other banks and customers.
Sadly, the Libor case reveals something rotten in today’s banking culture. We hope the investigations expose the bad actors, lead to jail terms for those who knowingly manipulated the market, and force out the senior managers and board directors who participated in, or overlooked, such conduct.
Why so exercised? In the Barclays settlement documents, regulators released smoking-gun e-mails that reveal the extent of the dirty dealing between bank traders (looking to protect profits and bonuses) and senior officials in bank treasury units (hoping to convince markets that their banks weren’t in financial difficulty). The two aren’t supposed to collude, but it’s obvious that the Chinese walls between them come with ladders.