@sgf Well ... sadly the standards for distributed lists will always succumb to the basic interests of the people who declare their own to be morally better than whatever they want to block.
And yes, i specially refer to mastodon.social and chaos.social ..... where you actually get a frickin instance block just because you might have a differing opinion to one of their users..
And because these instances have a relatively huge amount of users .... this actually creates problems and enforces recentralisation.
But that's just another completely bonkers aspect of the ongoing mastodontitis.
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Before you ask. i'm a left leaning german, i dislike what goes on under the "free speech" umbrella, especially if it promotes hateful or even violent behaviour against anyone.
But, you should for example do not _need_ to change your avatar image to a pride flag, just to avoid getting scrutinized.
That's why i'm not for a default opt-out block list.
Make it opt-in for easy access .... ;)