Some people may prefer not to be noticed in the neighborhood every time they ride, so they may not like a bike that stands out too much. Some enjoy the "spotlight" and use bright or fancy colored bikes.

What about the thieves' psychology? They notice a white colored bike locked to the pole sooner than a black one, but all things being equal, they might find riding away with the black one is easier for them. Also most cheap mountain bikes ridden by pizza delivery guys are black. Many expensive high end road bike are white. So that may be the impression to thieves.

This is from the view of someone living and riding in a populous city. It's a different story if you ride in scenic mountains, etc. (which I envy).