Dear Arso,
Let me clarify what is a kol korei.
When a Rav takes his stationary and pens his thoughts, that is not a kol korei.
Nor when a Beis Din signs their names to their own paper.
Or even when an organization all signs on a proclamation. (It is a real kol korei. But I wasn’t referring to them. They are badly outnumbered by all the junk.
I am talking about a letter written by an unknown hand, signed by a number of rabbonim that aren’t specifically in any one affiliation.
These kol koreis are worthless.
I have seen them being signed by the rabbonim. And have asked many times if the signee agrees with it’s content. I have gotten a wide range of answers.
If the rabbonim really agreed with the message, they would actively push it to some extent. Which happens all the time. So the proclamation itself, is just an empty ritual.
Their words get around just fine without these signed statements.