This is hard to explain, but this debate has about protecting culture. It always has been.
If some communities want a moat, that is their decision, not yours.
Some people came here because they didn't want to worry about their culture being disrupted by outside factors. To pretend this is not a real concern, as this blog post implies, is disingenuous.
https://indieweb.social/@tchambers/110693023583027761
The dogmatism exists because they're trying to protect their culture.
I realize it can be frustrating sometimes and there are real reasons to find it frustrating, but understanding why this comes up is key to understanding this entire messy debate.