You're still wasting your time. You're better off talking about him and not to him, though it probably won't change the responses he posts.
I see from his post that you quoted that he wants to know my opinion. I see no point in giving my opinion to someone who will just automatically disagree with me (because they can't accept that I corrected them years ago when they phrased something incorrectly - that's where it all stems from), he won't be getting it, no matter how hard he tries to engage me. No doubt he will claim that I am engaging with him because I mentioned him - so he must think that anyone who mentions Genghis Khan is engaging with Genghis. What about that Genghis, anyway? What the f**k was he all about? Mad bastard. (Hope Genghis doesn't see this and assume that I want to "engage" with him.)