I covered the federation issues in my other comment.
PieFed allows users to decide their own personal defederations without needing to depend upon an instance admin for that.
Hopefully as the UI gets more developed, people will gravitate more to PieFed, or Sublinks.
If the worst were to happen (another Ernst/Kbin.social situation) then any instance with only a single admin is indeed vulnerable, as is any instance that remains federated with it due to the inevitable spam attacks that will come from it.
Though the issues with federation with lemmy.ml are also important too. See e.g. that recent discussion at https://lemm.ee/post/45248880, where the admins expressed a desire for OP to physically commit suicide, all based on an easily preventable misunderstanding about a situation that happened in a game. Just to underscore how ridiculous what we are talking about is, here is a mini run-down of the facts: one non-existent irl character kissed another non-existent irl character, who had been dating in the game for awhile btw, having reached a "hearts" level of 8 of 10 points so quite an established relationship showing mutual interest, whereupon the 2nd character had just given a bouquet of flowers to the 1st one, who then kissed the 2nd one in a surprised and pleased movement, which the ML admins described as "sexual assault" (mistakenly thinking that that did not happen until reaching 10 of 10 points), banned the OP, oh and in the process also told the OP kill themselves. This sounds like insane ranting on my part I know, but it all actually happened!?!?!?! And it's not even something that we need to hear second-hand stories of, it's all right there in the modlogs preserved for anyone who wants to see directly.
It is because of events such as that - which KEEP HAPPENING - that I have stopped recommending Lemmy to anyone. Though I would love to start recommending PieFed as its UI improves a bit - and I will be helping that process along by submitting loads of bug reports to their team!:-) In the meantime, perhaps the downsides of instances such as lemmy.cafe being run by a single administrator do not seem so bad? After all, lemmy.ml has an entire team of administrators - but that did not stop SagXD from losing their account there, suddenly and without warning. Nor macniel or any of the others that we keep hearing about happening. That is why we are saying that having a single admin is bad right - b/c it is vulnerable to go down without warning? Afaik, I've never heard that lemmy.ml has offered a warning first before smashing the entire instance-wide ban hammer, even against a mod of a community there. Nor, again even for a mod there, do they even so much as tell them that it happened. Or explain what the cryptic modlog messages mean, which look at first glance as if they pertain only to individual communities, leaving people confused and having to figure out on their own what happened?
So anyway which is worse: a community with a single admin, or one with a whole team that is unhinged and somehow even more likely to boot someone, and with a demonstrated pattern of doing exactly that whenever it suits them?
And then ofc hexbear is a whole other thing too - who wants to be actively bullied, like why would that be fun for most of us, especially normies? If someone REALLY wants to be exposed to thus, then okay I won't stop them, but it really does seem to me like it would be helpful to at least offer a WARNING to new users that it is likely to happen. Which afaik lemm.ee does not do. Maybe as you recommend lemm.ee you can attach such a warning?
Possibly something like: "if you want an instance that is connected all servers across the fediverse, such does not exist but the closest seems to be lemm.ee, although be warned that it federates with known multiple instances known to encourage trolling behaviors; otherwise lemmy.cafe seems quite welcoming although it is small and with only a single admin so is less stable than others."
As you say, nothing is perfect. All we can do is try to help manage and perhaps mitigate this absolute shit-storm. Thanks for all your efforts there:-).
Here's such a conversation with an admin at sh.itjust.works if you are interested: https://sh.itjust.works/comment/12051373, or with the mod of traditional_art@lemmy.ml https://discuss.online/post/12722075/11762479, and ofc there are many more. One conversation at a time, bringing up the logical points, condensing them, helping people know their options, etc.
Not... entirely, but yes an entire section dedicated to "hardcore tankies" helps!:-) I suppose that helps more for people brought in via Reddit, but not word-of-mouth recommendations, so if I am speaking of the latter then the burden is on me, and upon everyone else doing likewise, to "warn" their irl friends that they recommend to take a look at Lemmy. Which is why I am saying that it would be good to add automated labels. I think we are still waiting for a Lemmy upgrade though, that would allow for those? Or perhaps people are waiting specifically for 0.19.6 when Lemmy.World will upgrade, leading the way.
Lemmy.World naively might seem the most likely to attach a warning label to Lemmy.ml communities, seeing as e.g. they have defederated entirely from Hexbear.net, whereas so many other instances do not even do that much.
Though for myself, the longer this goes on the less faith I have that it will ever be fixed whilst remaining dependent upon the Lemmy.ml + lemmygrad.ml admins & devs to help accomplish the goals of bringing in more mainstream normies from the Western civilization that they so abhor and constantly ridicule. Why should they? They themselves do not want that. It is a harsh truth but we are on their platform, and that's that. We will receive what they deign to offer. Which is why I am trying now to help PieFed thrive, despite how far behind it is, and it would be great to see Sublinks arrive as well.
You keep asking questions though... so I kept answering them:-P. I feel like we got some addditional clarity on your only focusing on the top 20 instances.
Little by little, progress is made. This issue is not entirely solvable though, using current methods available to us - e.g. the issue you mentioned that the desires of users to avoid being bullied are at cross-purposes with being able to access particularly the FOSS content such as !firefox@lemmy.ml. I will say that "accessing open source communities" isn't terribly hard - you don't even need an account for that, though indeed lacking one would cut someone off from participating by asking questions, posting, replying, and voting. Which is why something like a "community label" holds such appeal to me, and even more approaches such as PieFed's ability to enact user-initated user-blocking of custom user-specified instances without the need for the approval of an entire admin team and thereby the support of an entire community. It thereby democracizes blocking, making it available to anyone who wants it, which I for one think is awesome!?:-) Though the UI needs some polish, so I will focus on submitting bug reports to help with that.