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.
It can be both.
"Women drive badly" is a sexist stereotype, but not racism.
"Black people drive badly" would be both a stereotype and racism.
A better example would be, "women aren't passionate about driving". That's a stereotype, likely a correct one (i.e. substantiated by statistics... I mean, I'm not certain, but that would be my prior, but I'm very open to changing it), and most importantly: not harmful. It's just a stereotype.
I'm not denying that things could be harmful (racism, sexist, ...). But not all stereotypes are. Like guessing that "Alex" is probably a guy.
How about just not making any assumptions at all and ask and support people, be it white, black, male, female, trans, etc?
No, it's my experience showing. I grew up being basically ostracized (and also bullied) for being a geek. Little did I know it would turn out to be an extremely lucrative career. Simply, while other boys were out playing sports, or indoors playing computer games, I was programming. Because I was interested.
Having said that, I think it's also the case that some people are discouraged from doing what they want, because parents/society. I don't think I'm doing that though. If anything, I'd be more curious about someone doing something unusual (not even in an anti-stereotypical way, but like, generally - such as archery, or spear fishing, or (until recently) bread-making).
> How about just not making any assumptions at all and ask and support people
I definitely support people doing pretty much whatever. But experience shows that it's often better to e.g. lead conversations into interesting topics, rather than play a questions & answers game to find a common interest. The more you're able to do that, based on quick inferences, the better conversationalist you are (on average).