"At Mailchimp, when we write about a culture or ethnicity, we capitalize the name. For example, we capitalize Black as it refers to Americans in the African diaspora while we keep white lowercase since white refers to the color of a person’s skin and not a group of people."
The meaning of any word ultimately depends on its interpretation and usage, which can be highly subjective.
However, your description seems logically inconsistent.
Please refer to the second definition of 'black' and 'white' in the attached screenshots.

