But seriously, I'm kinda gobsmacked that Willco's pretending there's no racial connotation to the word in the US, when directed by a white person at a black one.
It's a cliche to have the stock Racist Southern Sheriff to establish what they are by having them call a black character "boy". In the Heat of the Night, Chiefs (John Goodman aims it at Lando Calrissian!), etc. Authors do this because they know the audience will understand the implication.
And yeah, it's pretty regional, and yeah, it depends on context. All words depend on context. No word "inherently" means anything. People share a precise, specific meaning for some words while others will carry a wider range of uses and connotations for those hearing them.
So while it's true that boy can be said with no ill intent, or with no racial intent even when it's an insult, it still carries a racial charge for a lot of people (including, I'd guess, the vast majority of black males in the US). I'm not sure I know any black guys who wouldn't be pissed if a white guy they didn't know called them that, and I know a few who would go complete batshit.