On Bluesky, users can create block lists that they can share with others. Subscribing to one lets you quickly block everyone who is on the list without having to check each member individually. This is convenient because you can simply block all the bots and spammers by subscribing to a block list of all bots and spammers that someone else spent months curating instead of having to spend months yourself blocking them one by one. On the other hand, block lists are delegating your authority to block people to a third-party, and there are dangers that come with this that you should be aware about.
Using someone else's block list means, essentially, that you have nominated its creator as your moderator. This is specially true on Bluesky, because the user that created the block list can keep adding users to the list, and everyone who has subscribed to that block list at any point will automatically block any new users added because they are now in the list. This is really no different from the job of a moderator. They can't ban users from the social media platform, but they can ban users from your feed, and that's practically the same thing.
When you subscribe to a block list, you are trusting that the person who created and maintains it has done and will continue to do a good job as your moderator. You're giving them that power.
When enough people delegate power to a person, we call that person an authority. This is how any system of government is formed, and, in my opinion, the main argument against anarchy.
Many people entertain the idea of abolishing the government and hierarchical structures, but when you look at users of a social media, and ignore staff and staff-nominated moderators, there is no established hierarchy. Every user is just a user. Every user is equal to each other in power and authority in this system. And yet when users need to start blocking things, it turns out that's just too much work to do it right, and they would rather delegate that to someone else. Nobody wants to have to investigate by themselves every single case, every single account, so that power is confered.
Just like in a real government, power corrupts. Users who maintain block lists that many have subscribed to can use those block lists, that power of theirs, to harass users they don't like. They can add the user to their block list, and by doing that the user will be blocked by lots of people who won't even realize that it happened because they aren't checking every user that is blocked, because that is too much work, that's why they delegated it to an authority.
If this sounds similar to what happens in real life when authorities abuse their power and nobody notices it because nobody is following every single case, it's because it's the same thing. It doesn't matter if the moderator is part of the staff or you just nominated your personal moderator yourself.
I don't believe there is any perfect solution to this. Everything will always have a drawback, and every time power is given to someone else, that power has the ability to corrupt someone who is corruptible, that power has the potential to be abused. It's just important to be aware of these consequences when you confer the power to someone else.