Lashon Hara is very important.  What I wrote in my previous blog could be looked at as on the borderline. I have tried to defend my thesis with the idea of "group  behavior." That is: when warning about a group you by the average behavior (which is easy to document and see). If you warn your children about a group, you do not need to see if every single person in the group follows the average pattern. 

  With this idea we can see why the Gra signed the excommunication. His signature was the top signature. 

Still, if this would be a matter of theory I would not say a word. It is from empirical evidence that I warn about the terrible hidden dangers that someone with less experience might not be aware of. I also have had myself and seen what I am writing about.

I am warning about that which I know about all too well and have had devastating and horrible experiences and I see their effects on others. I would be remiss in my obligation as a Jew not to say what I know about this subject.