I would argue that it's moreso that there are many more specific and clear social rules, but most people don't know how to explain them, so when asked, they just say "read the room". As another person said, it might also be a reminder or shorthand of something that you are assumed to already know intuitively.

I think part of the skill is tone, which is kinda dumb since the truth you communicate is basically the same. Even so, something like "I don't know why I'm alive anymore" might be considered rude while something like "eh" or "not great" or "same as usual" (hopefully that's not your usual) or even something like "well, I've been a bit overwhelmed by current events recently" would generally not be seen as rude. You can still say something that's true; you just have to soften things. It would be easier if the softening was not necessary, but as people have gotten at earlier, you have more power to change yourself that to change how the rest of the world reacts to things.

I'm not diagnosed autistic or any other form of neurodivergent. To the day if someone asks "how are you?" I might give a real answer. "Not good, my cat is sick and I'm worried he might be dying" was one I gave last year, to a food service worker. He gave me a discount that day, acknowledged that that doesn't make it better but he did something to show he saw me and we have been a lot more friendly since then.

I don't dump on him every time I see him, because I genuinely have good days, but he lights up when he sees me, and that makes me happy too.