I encourage you to consider and understand the perspectives of those who do capitalize the word.
This serves as an introduction to some people's thinking:
https://www.cjr.org/analysis/capital-b-black-styleguide.php
Note, the standard practice to capitalize ethnic groups: For example jewish would be considered incorrect. There are those who consider Black to be an ethnic group, hence, capitalizing it encompasses a way to "describe the people, culture, art and communities" that make up the ethnic group. In which case, it's not a color, exactly, which I think is what you may be missing, when you consider why some capitalize the word.
Case in point: We already capitalize many other groups that are often associated with "color." Color, of course, being a construct we often see as "real," when in fact it is a cultural interpretation.
> After all, she pointed out, “We already capitalize Asian, Hispanic, African American and Native American.”