The graph you linked to doesn't say what you claim it does – although it does point out the extent of intraracial crime in the black community. Despite that, you are correct that people identifying as "Black or African American" are about 52% of homicide arrests. That's an entirely different statistic.
The fact remains: whatever ethnic bias exists within crime figures, the statement "Most criminals are in fact black" is categorically incorrect, and basically the epitome of crass, racist statements.
There's probably someplace in the world this is true (e.g., I suspect its true in several sub-Saharan African countries), but its not either in general, or in the US in particular.
You mean like a work uniform, like the kind a mail carrier would typically wear, that is mentioned specifically in the article?