Oddbean

"Culture" is just shorthand for talking about the common sets of behaviours between groups of people. You can make it as small or as large as you like. Humanity at the broadest scale has a "culture" that can broadly be defined by examples like "pleasure is preferable to suffering", "we take care of our children", and so on. But you can also go the other way and take it down to the individual level. No two individuals have completely identical beliefs (or even consistent with themselves sometimes!). So ALL interactions between people could involve some level of "multiculturalism", purely depending on where you choose to draw the lines. Even at the less extreme ends of the scale, is it "multiculturalism" when a West Berliner and an East Berliner come together? How about a Berliner and a Münchner? What about a Münchner and a Parisian? Or a Parisian and a New Yorker? Or a New Yorker and a Hong Konger? Or a Hong Konger and a Mbabaner? etc etc. The entire concept of it being problematic for cultures to mix is fundamentally an anti-human position, and is generally just an excuse for racism or other kinds of xenophobia.

You make a great point about culture existing at different levels. For example, in my household, we have a culture of not wearing shoes indoors. However, this isn't because we're "shoephobic"; rather, we've found that it keeps our home cleaner. Guests can wear shoes in their own homes, but when they visit us, we kindly ask them to follow our house rule. My wife would understandably be annoyed if I disregarded this rule and allowed guests to traipse through the house in shoes. Our household culture has developed logically over time based on practical experience. On the other hand, if we had a rule like "no pink socks" without any logical reason, it would seem arbitrary and unwelcoming. On a larger scale, whilst we have nation staters (for good or bad), and because this is the level where immigration is controlled, it seems of relevance to try and define a culture at that level. Nation-states have their own cultures, often shaped by centuries of experience - slowly adapting over time. In the UK, for example, our culture includes following English law, which has (generally) served us well over time. For example, a significant part of this culture is that citizens do not openly carry firearms, and many would be angry to find out if border control had allowed large numbers of gun-totting Texans in with firearms. We have no issues with Texans open carrying if that's what they choose to do in Texas. However, it wouldn't be fair to exclude Texans based on say, wearing cowboy hats. (You know I always value your opinion Ben, all love here xxx)

But, I think the REAL issue, and where the anger should be targeted, is at the head of the household, who is either (a) inept at checking people remove their shoes, (b) on commission for everyone they let in, or (c) intentionally inviting them in to cause conflict and manipulate the household.