The mudcat, like other forums, is fascinating as a sociological phenomenon.
People who congregate almost inevitably fall into roles. Ever notice how, in every new crowd of which you become a part, you already "know" many of the individuals? In a general way, the individuals in the new group will remind you of the individuals in other groups of which you are a part.
The departure from this sociological phenom is that, in these on-line communities, there is a different standard by which individuals are evaluated and assigned their position/role. For instance, physical characteristics that command attention (beauty, stature, color, the ability to pull off "physical comedy" etc.) no longer apply, nor can they be "used" as tools.
It's been my observation that this results in immense frustration for certain individuals who for the first time, 1. Find themselves without their formerly reliable attention getting tools. or 2. Are misunderstood because their communication skills are overly reliant on physicality. (of course, the upside is that heretofore overlooked people can have previously unnoted wit and intellect really shine)
Consider also that, this being a music related site, the number of "performer" personalities is probably statistically, abnormally high. Remember Don Firth's description of how Walt Robertson instinctively knew how to become the focal point of the room? Imagine that those skills are absent, but you still desire what has (for you) always been your role.
Maybe flamers are the most frustrated by this new type of community.