The story has now hopped to the orange site. I was expecting a shit-show, but there have been a few insightful comments from critics of the rationalists. This one from "rachofsunshine" for instance:

[Former member of that world, roommates with one of Ziz's friends for a while, so I feel reasonably qualified to speak on this.]

The problem with rationalists/EA as a group has never been the rationality, but the people practicing it and the cultural norms they endorse as a community.

As relevant here:

1. While following logical threads to their conclusions is a useful exercise, each logical step often involves some degree of rounding or unknown-unknowns. A -> B and B -> C means A -> C in a formal sense, but A -almostcertainly-> B and B -almostcertainly-> C does not mean A -almostcertainly-> C. Rationalists, by tending to overly formalist approaches, tend to lose the thread of the messiness of the real world and follow these lossy implications as though they are lossless. That leads to...

2. Precision errors in utility calculations that are numerically-unstable. Any small chance of harm times infinity equals infinity. This framing shows up a lot in the context of AI risk, but it works in other settings too: infinity times a speck of dust in your eye >>> 1 times murder, so murder is "justified" to prevent a speck of dust in the eye of eternity. When the thing you're trying to create is infinitely good or the thing you're trying to prevent is infinitely bad, anything is justified to bring it about/prevent it respectively.

3. Its leadership - or some of it, anyway - is extremely egotistical and borderline cult-like to begin with. I think even people who like e.g. Eliezer would agree that he is not a humble man by any stretch of the imagination (the guy makes Neil deGrasse Tyson look like a monk). They have, in the past, responded to criticism with statements to the effect of "anyone who would criticize us for any reason is a bad person who is lying to cause us harm". That kind of framing can't help but get culty.

4. The nature of being a "freethinker" is that you're at the mercy of your own neural circuitry. If there is a feedback loop in your brain, you'll get stuck in it, because there's no external "drag" or forcing functions to pull you back to reality. That can lead you to be a genius who sees what others cannot. It can also lead you into schizophrenia really easily. So you've got a culty environment that is particularly susceptible to internally-consistent madness, and finally:

5. It's a bunch of very weird people who have nowhere else they feel at home. I totally get this. I'd never felt like I was in a room with people so like me, and ripping myself away from that world was not easy. (There's some folks down the thread wondering why trans people are overrepresented in this particular group: well, take your standard weird nerd, and then make two-thirds of the world hate your guts more than anything else, you might be pretty vulnerable to whoever will give you the time of day, too.)

TLDR: isolation, very strong in-group defenses, logical "doctrine" that is formally valid and leaks in hard-to-notice ways, apocalyptic utility-scale, and being a very appealing environment for the kind of person who goes super nuts -> pretty much perfect conditions for a cult. Or multiple cults, really. Ziz's group is only one of several.