> Let us now consider what a church is. A church, then, I take to be a voluntary society of men, joining themselves together of their own accord in order to the public worshipping of God in such manner as they judge acceptable to Him, and effectual to the salvation of their souls.

Where do you see "legally registered organization" in this defintion?

Of course, within existing legal doctrine, "separation of church and state" could only refer to legal technicalities. And that's the whole point I was making, that separation goes both ways. For you to redefine the idea behind separation of church and state in merely legal terms is itself a breach of that separation.