Before we knew who Jérôme Kerviel was or how he had managed to lose 4.9 billion euros, everyone was certain about what he was. For a few days, the phrase "rogue trader" bubbled evenly across the surface of the media stew like the "rhubarb" actors use to simulate the chattering drone of a crowd. Everyone, industry spokespeople, reporters, even the bank itself deployed the same words with the same tone of grim satisfaction that I imagine a surgeon uses to announce the discovery of a tumor.
And why shouldn't everyone agree? Rogue is such a congenial, multifaceted idea. For reporters, it's an easy, familiar way to generate audience interest. No one likes a criminal or cares about a mere perpetrator, but a rogue is dashing, never evil or boring. Like Robin Hood or Captain Jack Sparrow, he takes only from those who can well afford it and he does it with a swinging combination of freedom and style. (Note to JK: Loving the smoldering eyes of hatred, but you have to start smiling. If nec, get teeth fixed before trial.)
For the bank, it frames the loss as the result of an unsystematic, unforeseeable human character flaw. No point in outside examination, regulation or questioning of the system itself. Like a cancer cell, a rogue trader is a necessary part of the system that just started doing its job with a regrettable excess of vigor.
Especially (and ironically) in a world in which finance and computers often seem in league to dessicate the world into a highly profitable dust mote, a rogue may represent a sort of rebellion, but a safe and cynical one. It's no wonder that individualist escape fantasies like movies, cars, superheroes, romance novels and video games proudly carry the name.
Despite the many uses to which he can be put, the rogue is neither for nor against anything except himself. Maybe that's why everyone finds him so useful. You (and I) can map whatever we like onto him. Maybe that's also why the most appropriate calling for an ex-rogue trader is motivational speaker.