old.lemmy.world is just running mlmym, btw. There is another one running at mlmym.org, where you can use any instance. Or you can run the software yourself if desired.
It's because they were giving free domains for a long time. Then when they were recently being revoked, Dessalines paid for the domain to keep it (I'm guessing to avoid losing the current community+their m+l origins?)
And who builds them? Rich people. Who continue to act the way they do. It's not as simple as just building more, the system needs to change completely.
So it looks like it's mostly to do with the account system of Firefox. I'm not sure why their websites would need special protection, but whatever. It's not malicious, for now
old.lemmy.world is just running mlmym, btw. There is another one running at mlmym.org, where you can use any instance. Or you can run the software yourself if desired.