Seems to me the solution to this is registering protocol handlers for URLs, which Mastodon tried and gave up on because they weren’t happy with how web browsers handled it.

If your questions are concrete and in the context of Lemmy or the Fediverse more broadly, admins provide the service of paying for and operating the servers in addition to moderation.

If it’s more abstract, i.e. “can people talk to each other over the internet without moderators?” then my experience is that they usually can when the group is small, but things deteriorate is it grows larger. The threshold for where that happens is higher if the group has a purpose or if the people already know each other.

I dislike it. I already have a unique, long, randomly generated password for every account. That’s stored in a password manager with a unique, long passphrase. 2FA provides very little additional security in that scenario.

Worse, many services won’t let me use a standard TOTP authenticator. Some insist on SMS. Worse, some insist on their own app.

I’m sad PGP didn’t become a popular way to log into websites. A challenge-response protocol could have even been built into web browsers. Big tech is reinventing that idea as Passkey, but with a very big tech flavor.