Why do the British say the opposite of what they mean and call it being polite?
A conversation between two people has a shared meaning that you construct together, right? Like if we have a conversation, we have to come to some agreement about what the takeaway from it was. "We passed the time," "We discussed politics," "We flirted," or whatever.
The British conversational idiom isn't about saying the opposite of what you mean per se, it's about giving your conversational partner enough interpretive room that, if they want to, they can retroactively change the shared meaning of the conversation without explicitly acknowledging that that's what they've done, and so save them from embarrassment. An example would be two people having a conversation that could be interpreted as flirting, or as innocuous. By being indirect, they give each other room to either advance by becoming more direct (making the takeaway "We flirted") or back out at any point (making the takeaway "We chatted about how fond we both are of our platonic friendship") without having to make themselves emotionally vulnerable by actually saying what they want. Which is why some British people find it rude when you back them into a conversational corner and the only way out is to actually say what they want explicitly: it's considered rude to force other people to be emotionally open. The whole point is that you're supposed to play the game together in such a way that you don't have to do that: to fail shows either a lack of conversational skill or a lack of care for your conversation partner's feelings.
None of this is ever made explicit, of course: that would be rude.
That's why many Americans are rubbish at verbal flirting, but they make excellent long-term relationship partners.
So do autistic people in England just die
