Through no fault of our own, I should note. We're basically permanently associated with something Roko decided to post one day. We did not spread or popularize it; quite the opposite.
The Basilisk has seen enormously more use as "a thing rationalists believe" than as a thing rationalists actually believe.
As a mod you have to delete harmful things. I think the spread of Roko's is entirely due to its own memetic strength as an idea, and the Streisand effect has very little to do with it past the first dozen people who saw it.
We also have done nothing to signal-boost the Zizians. :) If we can be accused of anything in this context, it's not kicking bad people out aggressively enough, which seems very different from fostering bad ideas. Zizianism is not a widespread ideology in rationalist circles, in fact it was confined to a very small circle right around Ziz themselves. It unfortunately is the case that we have a lot of psychologically vulnerable people and we don't always do the utmost we can to protect them, in large part because a lot of rationalists have trauma about being excluded from communities.
> If we can be accused of anything in this context, it's not kicking bad people out aggressively enough, which seems very different from fostering bad ideas.
It's not very different. It's barely different at all.
Right now, I have five tomato plants growing in my garden. Two of them I planted; the other three grew from seeds left in the ground by tomatoes that dropped from plants growing last year. All I did was refuse to uproot them when they sprouted. Five healthy plants, with different origins, but the differences are largely insignificant.
Groups and behaviors are much the same way. I've worked with hundreds of moderators over the years who wished to keep their hands clean and yet express some sort of dismay as to the sorry state of the communities they were nominally responsible for... Such moderators, like a gardener who does not want dirt under their nails, are best encouraged to find other hobbies.
Yes, it's a balancing act. It should be noted that abusers also tend to be very good at painting people dangerous to them as abusers, so it's difficult to start with. Generally speaking you look at a person talking about vegetarianism and decision theory to some other people in a corner, and you don't usually think "this will end in them murdering their landlord with a samurai sword." We at least managed to ban her from the community after the suicides, which was still well before she became famous, and before that I can only say that it's just very hard to notice that you have to ban a person from a community if she's mainly keeping to herself and talking.
I can't speak to your specific scenario, but in general a "balance" that is missing in many communities is a clear line between pedagogy and research (or debate). Often this is because _initially_ the community is small and the distance in knowledge between members is minor - debate and knowledge-sharing go hand in hand. As the community grows though, the number of people joining who have little or no baseline knowledge compared to the founding group grows larger, until eventually it dwarfs the size of the core group.
This is when co-mingling becomes actively dangerous. New members may (often, will) lack the necessary knowledge to identify core vs. fringe beliefs, to contextualize debates, to recognize insider "shorthand" for what it is, etc. They need (and are possibly even looking for) a useful education, not to become test subjects or disciples. They _cannot_ be engaging in useful research at this stage, even if this is what they wish to do (there are some unfortunate status-seeking behaviors that can come into play here).
Also coming with this scale are a crap-ton of meta discussions concerning basic community governance, including those around "how quickly do we have to kick out crackpots to keep them from recruiting here?" Those discussions _also_ shouldn't be co-mingled with the educational structure, although it's good for new folks to have some visibility into them and at least know that this sort of governance _exists_ in a tangible way (because if it's opaque, that thing you noted about crackpots playing victim becomes a LOT more effective).
This is all a huge amount of boring, tedious work, and... An awful lot of communities start in on it waaaay too late or don't bother at all. What if it stops being fun and exciting and everyone leaves? Of course, there are worse ways to go, but folks tend not to think about those until after they've happened.
The Basilisk has seen enormously more use as "a thing rationalists believe" than as a thing rationalists actually believe.