Is there any verifiable evidence that 'The Service Committee at JW Branches will automatically bin any anonymous letters which highlight "flaws" in a JW dogma'? It seems to me that probably is done to most such letters, but I'm not sure it is done to all of them.
We know that the WT sometimes starts teaching ideas which they formerly considered apostate teachings (of JW's who became expelled for such teachings). We also know that the WT sometimes changes policies and sometimes revised the wording of the NWT due to caving into pressure by ex-JWs critics of the WT and by critics of those who never were JWs. We also know that the WT makes uses of theological scholarly books by that which the WT calls Christendom. However I release that most likely in all of the above examples, the critics of the WT probably didn't write anonymously.