'The Black Boy' always struck me as an odd name for a public house, most of these have been rebranded with Caucasian children working as chimney-sweeps (as if that is much better) or other re-interpretations of the idea.
However, these pellets are very much explicit in their 'British Empire' symbolism.
I'm not sure what it is supposed to mean? If it was a white woman with red hair, and they called it 'Red Girl' pellets what would that mean?
I know John Darling used Danish 'Black Box' pellets when he was a professional pest-controller in the 1970s, but that is because the pellets came in a black carton.
Advertising and marketing is a weird part of human culture.