Where this has gained some degree of attention today for the #Universeodon (and by extension #MastodonAppUK folks)
I have made use, for a while now of the minimum block list provided by @oliphant - This list combines the public block lists of a number of mastodon instances including some that I personally have had previous issues with. However, the minimum list has proven to be almost always spot on when it comes to removing servers that are known to be problematic for a range of reasons.
A couple of weeks ago that list got imported here to Universeodon, and there were a small handful (5 maybe) servers that had some existing relationship which we severed as a result of the import, which was an intentional decision on my part.
The intention behind bringing the list in was to start to align our moderation with MastodonApp, but to also try to ensure we aren't reacting to reports constantly, and that we can prevent our community from having to see content that may be upsetting.
Now I'm not glued to this list, if genuine issues are raised that can't be resolved, I'll stop using it going forward, but to date we've never had a single instance contact us and ask to be removed from our block list and we've had only one user that has even noticed it impacted them.
I'm always happy to have a genuine and open discussion if there are real concerns with the list we're using, from my experience running it over on MastodonApp.UK, it's proven to be a really solid list, and it's near impossible for one off issues to result in being added to the list, combined with the fact we don't stream the list in, if servers do get added and quickly removed, 99% of the time we never even know they had ever made it onto the list.
This doesn't mean we have or will stop adding servers manually, but it does give us a head start and tries to mean we're dealing with the new servers where our community has had to see something and report it.