Most likely, it comes from presence of light vs absence of light. White is the color most representative of presence of light, while black is the color most re

Most likely, it comes from presence of light vs absence of light. White is the color most representative of presence of light, while black is the color most representative of absence. In many religions, light represents truth, while darkness represents absence of truth. The good guys shine the light, bad guys cover it up. No reference to race is required for this well known symbolism. The old westerns were shot in black and white, so it was easy to have the white hats be the good guys and the black hats be the bad guys. Easy identification by the audience as to what was going on.