I hesitate to add anything to the Hoffman debate since I've not read his
book, but, nonetheless, I will make one comment:

One of my heroes--the late, great Carl Sagan--said that extraordinary claims
must be supported by extraordinary evidence.  While Sagan was talking about
UFOs, astrology, and the like, I've kept his dictum in mind as far as
literary criticism.  In other words, if someone is to argue that Twain had
homosexual relationships (certainly an extraordinary claim!), the argument
had better be supported by concrete facts, not suppositions.

At any rate, I like forward to reading the book.