I think it could be this way too. But, for example, in MonstaX's `Follow`, in the end, all members are climbing that masonic stair, NCT has similar concepts too. In G7's 'Not by the moon', all members are wearing that black clothing and are around that sacrificial table, the same with BTS's 'Fake Love'.In my opinion most of the idols do not suspect and do not attach importance to this.
For example, G(I) - DLE, in my opinion, only Soyeon is initiated, since She writes lyrics and music, while other members rather blindly trust her and do not suspect what they are involved in.
If only one of them is initiated, then why all members are shown climbing that stair/wearing that black cape? Or is it that the only one sitting on a throne is 'truly' initiated?