So "culture" and team cooperation and coordination are not things you place any stock in?

Team cooperation is not something a cover letter can tell you. "Culture fit" is nothing but an incredibly transparent and convienient post-hoc justification for when you know you're only excluding someone for not looking or behaving enough like you but have to find some way to word it that doesn't make you sound bad.

Doesn't everyone expect their coworkers to behave somewhat like them? I suspect you'd be pretty unhappy if your company hired someone who went around making crass jokes all the time - I certainly would be.

In that case the problem is that you've hired someone that lacks the emotional awareness or worse doesn't care that they're making people uncomfortable with the jokes, not "bad culture fit". Whether someone cares about how their behaviour affects others definitely sounds like something that should affect a hiring decision.

The key insight you're missing is that the concepts of emotional awareness and comfort are themselves "culture fit" standards. Different cultural groups have wildly different perspectives on how emotional awareness is properly expressed or which kinds of comfort people are entitled to. To pick a hopefully non-controversial example, there are some people who are most comfortable when they're allowed to have pink hair, and others who feel that showing up to work in pink hair reflects a lack of emotional awareness.

Thanks for this key insight, but I don't see how it's relevant.

The point, which I'm very far from the first person to bring up, is that the actual purpose of vague concepts like "culture fit" is to be a wildcard you can use to exclude anyone without having to critically examine or provide an actual reason. How you personally justify having pink hair not being a "culture fit" to yourself doesn't change anything about that. What it does change however is that you now no longer have to explain that you're not hiring someone for their hair color.

There's no need to invent hypotheticals, by the way. The people I've heard asking how they can stop getting denied for "culture fit" in interviews have one thing in common and it's being >40 years old or a woman.

I agree with the first part of what you're saying. The purpose of concepts like "culture fit" is to encode the idea that human interaction can't be easily reduced to numbers and checkboxes, so people can be a bad fit for a team even if there's no specific job requirement they don't fulfil. You can go too far and end up with an exclusionary team only accepting carbon-copies of each other, certainly, but the idea that the entire concept of fitting in is fake seems too far in the opposite direction.