Language functions not only as a communication system for a group but also as a value system which defines the mental life of the Chess.com members here and thus is a prime contributor to stupidity. On the positive side, language obviously makes it possible for people to discuss problems, processes and phenomena of which they are consciously aware. On the other hand, language also (and much more subtly) affects the process of perception and makes it so ambiguous that people can accept clear discrepancies between their beliefs and actions in many important, ego-defining situations.
With perception rendered so ambiguous and subjective, stupidity is invited, if not actually promoted, as people usually can find some verbal framework in which they may rationalize their behavior and some scapegoat or excuse to explain away their failures. Thus, language is an obstacle not only to objectivity but also to cooperation among diverse groups. Worst of all, language keeps people from understanding what they, themselves, are doing.
With everyone using the same biased language, it is unlikely that members could develop original, self-correcting ideas. Hence, it is difficult for an insider to form and usually stupid of him to offer an objective, critical analysis of his reference group, whatever it may be. Any attempt to do so would most likely be regarded as heresy and the critic shunned or dismissed as a threat to group integrity. (In fact, the only thing more aggravating to a group than a critic is an idealist who lives up to its stated creed.)
People indulging in groupthink find themselves not only invincible but invariably right according to their own standards. This presumption of inherent morality usually means that no one in the isolated group will question its basic beliefs. Thus, members are likely simply to ignore ethical and moral consequences of their acts, since they assume they are right and what they are trying to accomplish is obviously good. Of course, if actions against an out-group are under consideration, the enemy is stereotypically viewed as evil, weak and stupid and is accordingly referred to in disparaging terminology.
It is interesting to compare the actions in a forum to those on a chessboard. On the chessboard, the fundamental thing that gives the game order and makes it interesting is that that we all know exactly how the pieces are permitted to move. In a forum, the rules of conduct are intended to have an analogous effect. For example, there is a rule on pretty much every forum against personal attacks and insults towards other participants, which makes discussions much more constructive. But like a chess player who insists on knocking the opponents pieces off the board between moves, there is always someone who delights in the freedom of ignoring such rules completely. I imagine such people never realise how immature it makes them look.