I feel like you’re either not understanding me or dismissing what I have to say.
To put it simply: KG doesn’t care about people aside from religion. Why would he? He wants them to help him eat their planets, that is all (he is titled, “the planet eater”, after all). This is what I constitute as “religious communication”— He is only providing them information in the interest of advancing this sole desire, and has no use for humans outside of that. Please, name something that the Exif or Ghidorah do that doesn’t boil down to “So Ghidorah can eat their planets.”
Garbetrium bead? Only so he can become corporal and eat the planet.
Gematron calculation? In the interest of advancing their religion & arriving to new planets so that they can convert the inhabitants… and Ghidorah can eventually eat them.
That weird water thing Metphies did to his followers? Ghidorah ate them in that scene.
A religious leader would be someone who leads others to “salvation”, yet is not worshipped themselves, like Mother A from Escape the Deadzone. She gives sermons and tells her followers what to do, but they don’t worship her. Ultimately, the god is Godzilla, and she wouldn’t be under the same banner as Ghidorah because she is not the people’s god.
On the other hand, most of the Exifs have no desire to do anything other than be religious. In the United Earth Significant Report on Exif, they are literally trying to convert the researches as they are talking to them, using their advanced technology to spout why their religion is so great and why the researches should convert to it. Obeying what he says is part of their worship, not aside from it. This is why the leader description (for Ghidorah) falls under what it means to be a god.