While I think that not reading a book you have no interest in is perfectly acceptable, condeming the same based on heresay is - well the character in the film came across a bit shrill.
I know two people that were in the senshusei course with Robert Twigger, they are both my sensei's. They both have the same opinion on the book, and on Robert Twigger. They both feel they were poorly portraited in the book. I am basing my understanding of the book and Robert Twigger upon what they told me, and I have no reason to doubt anything they say since they are both intelligent, whole hearted, and truthful people. I have no reason to doubt them or the experience they had with Robert Twigger. They arent the only ones with this view either.
If the stories about him are true,(ex. jumping for joy upon hearing of Gozo Shiodas death) then I have absolutely no respect for him or anyone that shows this kind indignity.