This has been brewing for some time and the original plan was to only hide them from the "All" feed so that they would not pollute our member curated federated feed, but the feature to do so is sadly very inaccessible in Lemmy (hidden as a admin only API command that isn't exposed in the UI, making it a real hassle to use).
But these days these bot spam instances started to take up a lot of space on the federated feed, so I feel like full defederation is warranted now.
The bot spam instances identified so far are:
Additionally there are some bot accounts that are solely reposting RSS feeds and thus should also be banned:
This is a work in progress list. Feel free to suggest additional bot spam instances or accounts here in the comments. Thanks.
P.S.: If you run a individual RSS post bot for a community you moderate here on SLRPNK and it isn't spamming the federated feed with an excessive amount of posts, then there is no need to remove it.
Edit: the above instances are now defederated and the bot banned.
Thanks and added to the list.
We intentionally are a smaller themed instance that doesn't interact with any bots that fill the federated feed with posts from other instances automatically. This results in our "All" feed being much more usable than on other instances, but it also requires some curation if a single member decides to subscribe to a high post volume bot driven community as that drowns out all the organic posts shared by real users.