> But sure, only compatible cultures should talk to one another?
No, this would be taking my argument too far. Online communities develop their own cultures and norms, mostly borrowed from the real-world cultural contexts of their constituent members. Someone trying to participate in a community without conforming to those cultural expectations is going to cause trouble.
> So which cultures pair well with yours and which don’t, then? Who would you kick off the Internet/social media?
I see no reason to kick anyone off social media, but I think unfocused social media platforms like Facebook, Twitter/X, Instagram, TikTok, &c. are causing social problems. There were Americans in America protesting against coronavirus lockdowns in Australia, and there are Australians who have reoriented their entire identities around Donald Trump and QAnon: people are being radicalised about events that have nothing to do with them, and over which they have no control.
The social media I want to see is the old-style message fora that existed before modern social media: phpBB- and vBulletin-based communities that were designed around shared interests, not platform functionality.
Moderation is a real problem for modern social platforms. In the 90s, we had the so-called Scunthorpe Problem: AOL users living in UK towns like Scunthorpe and Penistone were banned from the AOL support forum for giving honest answers to inquiries into their location. The problem persists in a more subtle form, even on this website, in the Forbidden Meatball Problem[0].
Interest-based online communities would be able to carry out their own moderation according to their own cultures, and consequently avoid these problems.
[0] https://www.thetimes.co.uk/article/british-dish-encounters-q...