I will not address the trademark issues other than it is not as simple as saying that the first commercial owns the trademark.

You have left important details.

Is it the intent of Mr. White to mislead people into thinking they are dealing with Mr. Black?

Is this name very distinct or is it generic sounding. If Mr. Black's business name is antique casino chips, I don't think registering a website as antiquecasinochips.com is a clear case of stealing a name.

how widely known is this business name? This relates to the first question.