I've recently been reading/watching some videos and writings by Robin Diangelo on systemic racism - here's a great starting point: https://www.youtube.com/watch?v=h7mzj0cVL0Q. She also wrote the book "White Fragility".
Thinking about that, I'm just wondering how different it would be if one of those people who mistook the employee for the CEO instead turned to the CEO and said "I'm sorry, please excuse me for the instance of racism I just perpetrated against you, I promise it won't happen again." I realize how outlandish that may sound writing that out, but I'd propose that the fact that it does sound outlandish is the main problem. Everyone in the US was raised in an environment that inculcated certain racial ideas, subconsciously or not. We can't address them if we're so embarrassed by their existence as to pretend they don't exist.
Why would the person on the victim end of this feel humiliated? I suspect,at least in part the body language offense and humiliation contributes to the awkwardness. Now, if they insist on treating the guy with less melanin as the boss even after being corrected...yeah, who wouldn't be pissed.
Why wouldn't they? Being unfavorably stereotyped is almost universally frustrating and humiliating, regardless of any systemic concerns about racism and the like.
Wrt. the case mentioned by parent, it seems clear to me that the person involved should definitely apologize for their social faux pas and mistaken assumptions-- and that seeing them refuse to address the issue for fear of being regarded as racist or whatever would only result in even more frustration.