Thanks Leo for this series on Rutherford's smear campaign against Moyle.
I think it needs to be clarified what Moyle might have meant by his statement that he "did not circulate" the letter.
As you pointed out, he did show the letter to some people. He also refused some requests for the letter that he received.
When the letter was read at Bethel, it became public and ceased to be private.
It was Rutherford who decided, not Moyle that the contents of the letter be made known!.
The congregation reporting that Moyle was distributing the letter and giving talks about it appears to have been "circulating" gossip as fact.
The Watchtower was also kept stirring up things by publishing "loyalty" testimonies from individuals condemning the man.
Rutherford attitude towards Moyle was this, "You libel me privately, I'll libel you publicly!"