That way, they can make the religion look like they are going mainstream, while clamping down all the harder. The Showcase Edition of the washtowel could have information that makes salvation without joining look possible, while the Kool-Aid says that not only you have to be a member, but you have to be totally whole souled. The Showcase edition makes it look like education is encouraged, but the Kool-Aids make it clear that it is not. The Showcase makes it look like field circus is only a few hours a month, but the Kool-Aid makes it clear that they want everyone to pioneer. And so on.
And they tell me that the "secret" societies are all bad. The core is deceptively simple, and anyone can see the core of their doctrines without being turned off. If anything, they strip off the hype and the superfluous rules that obscure the truth, and expose the simplicity of morality. If it's good for self or society, it's moral--if it is bad for self or society, it's immoral. You don't get any simpler than that--and that is not going to turn off people. (And no, there are no hidden interpretations of "good" or "bad", either).