Serge,, if they're a thief and you can prove it with a case or 2 then state it. They are people like everyone else. Just because they might have Hitlers shirt, or some diamond studded badges etc. means nothing. None of them are better than you, I , and the rest of us....
Actually,,when there is a dealer that has sold fakes, sold pieces knowing they're fake [proven] then its a dis service not to let your fellow collectors know..