I would say that the in-group jargon is more of a retention tactic than an attraction tactic, although it can become that for people who are desperately looking for an ordered view of the world. Certainly I've seen it a lot in recovering Scientologists, expressing how that edifice of jargon, colloquialisms, and redefined words shaped their worldview and how they related to other people. In this case here, if you've been nodding along for a while and want to continue to be one of the cool guys, how could you not glomarize? Peek coolly out from beneath your fedora and neither confirm nor deny?

I will agree that the ratsphere has softer boundaries and is not particularly competently managed as a cult. As you allude to, too, there isn't a clear induction ritual or psychological turning point, just a mass of material that you're supposed to absorb and internalize over a necessarily lengthy stretch of time. Hence the most clearly identifiable cults are splinter groups.