I also think that its the divorce between the human interaction that we evolved to deal with and the speed and ease of communication these days.
Hiding behind the keyboard allows a lot of things to pour out of people that they wouldn't say in public or face to face.
The other component is that it would also tend to attract a higher proportion of folks who lack social graces as a result of upbringing or mental inclination.
Sme interesting studies in Pschology are bringing to light ( as told to me by my niece's boyfriend studying this) the fact that psycopaths and sociopaths flourish among us, but the better ones learn how to interact to avoid detection. In fact it can be seen as a recipe for success in spheres like big business.
The real puzzler for me was the chosen screen name.
I've not had any success with the numerological significance of this so far.
Perhaps there's a high-function sociopath out there who's a math wizard who can shed some light on this?
Of course, the "just plain rude" thing also works as an effective explanation.