What do you think of the claim that the Mahatma Letters to Sinnett were never supposed to be published? Supposedly, the editor made the choice of publishing them after his death. There is also the accusation that they don't accurately express the thoughts of KH and M. I suppose, all of the foregoing could be admitted and yet they would remain a valuable documentary resource.
A key component to the claim that they were not to be published is the belief that letter #39 is not authentic, because that letter does seem to license their being open.
I must say, I dislike what I perceive as taboos within Theosophy. I prefer the approach that everything is open, for scrutiny, for edification, or just for exploration. To me, any author may be studied, and any source of insight, even if it is "behind the scenes" can be considered useful.
Many of you are far better scholars than I. What do you think of the letters. Were they meant to be kept private.