Well, not all of his posts are that long. Most of the time, thirdwitness debates members of this board regarding Watchtower chronology.
At one time, I felt exactly the same way you did. I suggested that everyone ignore him. But then, someone (I believe it was hillary_step) made a very convincing arguement against my view. They pointed out that there are may JWs who read everything on this site, but don't post. They just quietly observe the debates that go on. This is a very healthy thing, because we JWs come from an environment of totalitarian control where absolutely no discussion, debate, or disagreement is allowed.
It is a truly amazing thing to see a devout WTS supporter (some believe to be a Bethel operative) and posters on this site have open debates. Where else could we see such a thing?
So, I am irritated by thirdwitness' staunch apologies of the WTS, but I am glad that he is here. I think it is a very healthy thing to have these open discussions and debates. The Watchtower Society must be cursing the internet.