[Lonesome in Massachussets]

“We don’t want the word to go out that we want to exterminate the Negro population, and the minister is the man who can straighten out that idea if it ever occurs to any of their more rebellious members.”

I think it's pretty clear from the use of the words "straighten out" that she considers "that idea" to be false. She could have been clearer. I don't see a smoking gun in this letter.

[Popman]

I think you need to reread the quote especially the last words: if it ever occurs to any of their more rebellious members.”

Very clear on her meaning...the minister was to get the minds right on any rebellious members who thought they were there to exterminate the Negro population.

Just like today's progressives...lie enough times until the truth is hidden...