The internet could be the ideal place...
...and a safe harbor to social misfits, handicapped (mental & physical) people, those who have failed in life but have another shot to make it in this medium in fantasy. Very easy and convenient.
The dark side of people can be safely bared (no law and order or Police to induce lawful behavior) in this domain and not all posters may be also as bad as the impressions they leave based on few posts.
Though, I believe, by and large, over a large number of posts, the world of the poster can be outlined and his thinking and thoughts may be exposed without social restraint in a real life situation.
I agree with your reaction in response to the poster you mentioned. I too, do what you do. Who knows, probably many feel the same way as we do. Without a reason or function to be on these message boards for full time, makes one really wonder...