There is a fine line that people like us would do well not to cross, and as most people here have already said, that line separates criticism of a player's football ability or performances from personal criticism. IMO, professional footballers need to be able to take a look at what people may be saying about their football, even if some of the criticism is harsh. As has been said, for every bagger there is usually a defender. Also, I think a lot of the time criticism stems from supporter passion - we all want to see our club win, so we get worked up over what prevents those wins.
Overall boards such as this one are mainly positive, and are nothing more that a place where supporters can share news, ideas and opinions. They are just that. Opinions. Mark Robinson has blown a legimitate topic out of proportion.