Black is not necessarily the color of the "bad guy" when you consider Asian cultures, and the director Ang Lee is Chinese/Taiwanese and a follower of the I Ching.
What does black represent then? Well, black is night, feminine, left, water, and many other attributes that complement and are the opposite of white. Black is as essential as white is. It's like left and right. And in everything black, there is a touch of white, just as in everything white, there is a touch of black. You can't have one without the other.
