He was banned some time ago. I am thinking about 3 years ago.
He did not always play well with others.
He had a tendency to engage in pointless/endless arguments with some other posters that led to problems. In short, he ran afoul of the mods and that was that. Not sure exactly what the last straw was, but evidently there was one.
Don't know if he is here under another name but I would not be too shocked if he was as he had been posting here for years. Even back in the days of the old pre-2004 board. And yes, he was a knowledgeable poster.