Although I can't find the story I know I read a woman's experiences with sexual abuse and Yudkowsky's BDSM habits there sometime in the last year. Actually I believe she posted it then committed suicide; people on LW responded by complaining this was an unfair way to start an argument.
I read LW pretty regularly (FWIW, I don't live in a group house, am monogamously married, and expect superintelligent AI to arrive slowly and be less exciting than many LW types hope or fear) and don't remember seeing anything there that matches what you describe -- though of course maybe it was deleted or something.
But there is this: https://www.lesswrong.com/posts/s93F5JmhCxKDxWukD/rememberin... concerning someone who committed suicide and (though this isn't mentioned there) left a suicide note describing her experiences of sexual abuse in the rationalist / Effective Altruist community. Nothing to do with Eliezer Yudkowsky in there, though, so far as I can see.
There is a comment in that thread that could very uncharitably be said to match your description. It's a response to someone saying "she complained about such-and-such failings in the rationalist community; let's change for her" (the failings in question aren't, or at least don't appear to be from the description in the thread, about sexual abuse), and the reply is concerned that spreading the message "if you complain about things and kill yourself then that's an effective way to get the things addressed" is dangerous because it might encourage people to kill themselves. Which might be wrong, but is pretty different from complaining that committing suicide "is an unfair way to start an argument".
Anyway, this is all a bit of a digression. As to whether Less Wrong is a counterexample to the claim that every online community with active moderation gets described as "toxic": no, it certainly isn't, and plenty of people have called it toxic. For what it's worth, I think it's a distinctly less toxic place than it was (say) three or four years ago. (The website was rebuilt from scratch and a new team of moderators installed, and both of those made it much more feasible to deal with the small but vigorous group of neoreactionary loons who had been making things unpleasant there for everyone else.) And for sure it's much less kooky than the real-world Bay Area rationalist community is alleged to be.
This is probably a hammer and nail thing, but having just heard a podcast about disinformation campaigns (https://samharris.org/podcasts/145-information-war/), your comment shares some traits. The podcast discusses that one of the main things "they" (those behind disinformation campaigns) do is putting groups up against each other in various ways, highlighting the differences rather than the similarities. Regardless of whether you're actively trying to do that (I would assume not, you're probably unaware of the effect this type of comment has), this is exactly the type of comment that creates an us vs them environment and highlights the very, very worst stories of what you perceive to be the other side. It's one of the least constructive things you can do online.