I think the lack of a leader is a red herring.
Modern cults have leaders, but Genderism is I think more like the Greek and Roman Mystery cults, built around eosteric hidden knowledge, a deeper reality beyond the real, transformation, and body-centered rites of mortification or indulgence to move the believer beyond the body, to transcend (pun very much intended) the body as a limiting factor on the self.
Genderism tells us we cannot trust the clear observation that the vast majority of humans are very clearly of one sex or the other because men and women are not really the names of the sexes, but "really" the names of two sorts of inner gender.
This inner gender is simultaneously so absolutely fundamental an aspect of our humanity that it is really gender rather than the readily observable difference of sex that gives rise to the knowledge that humans can be "men" or "women" in the first place, is far more important and significant to our social and romantic identies and realtionships than mere body sex, yet is also so mysterious and unknowable that it can never be explained or even described, nor even just the differences between genders, so hidden and personal that no one can ever know what another person's is unless they are told.
(Albeit with the very weird nuance that even though Genderists apparently can't describe what a man is, or a women, or list any stable difference between them, nevertheless they are absolutely unshakeably convinced that whatever it is, it sure as hell needs different toilets! 😂)
But all this cannot be proved, it simply has to be taken on faith. One is told it by someone one trusts. The authorities and establishment seem to believe it, ones peers seem to see it clearly, and so one takes it as truth and then looks at ones own life and reframes ones own experiences against that narrative.
But once "truth" is located not in the everyday we can all see, a shared reality we can discuss and share, but somewhere else not directly perceivable, we cannot challenge it. We cannot trust our own interpretations of our own experiences, we need to be guided to the "real" truth, something we have to be told and take on trust. Our own first person observations are delegitimised.
And so even without a directing and benefitting "leader", power still devolves to those with the confidence (often through genuine belief) to speak with authority about this unknowable thing and therefore able to provide the safety of certainty to those who no longer put trust their own perceptions and judgements.
Thinking about it, it's a dynamic that is really common in online fandoms and hobby spaces. "Truths" like, oh the "best" version of a certain tool, or a superior technique that marks one out as a pro, become established as common knowledge and get repeated and shared by people who haven't actually learned it from their own experience but simply read it posted with authority so many times they feel confident in passing it on themselves.
So perhaps what we are really seeing with Genderism is the first religion/cult to emerge from the mechanics of online interactions?