It's just human nature. All we are is a bag of chemicals with complicated wiring. Some of it is hardwired through our genetics and some is coded through our experiences.
Most people react negatively to perceived aggression. Depending on how a person is wired it could be a fear response or an aggressive one. Human nature makes people less fearful when separated by distance and more likely to be aggressive.
The internet forum is the ultimate distance since you are separated by time and space. You don't have to be in a real time confrontation complete with attendant emotional triggers, you can compose your words as you like at your leisure and choose the time of response. And you have no fear of physical reprisal as you would expect in a physical confrontation. So with that inhibitions and social restraints fall away and people allow themselves much more latitude.
For example:
I said this about a certain member's post when he gave a flippant response to a serious question, "don't worry about it, he thinks that he is a comedian." (fairly harmless comment I think)
The anonymous member then gives me negative red rep with this as the comment, "You're a f**king idiot."
Now, if we had been standing around in a bar and the same conversation had taken place then I am certain that the person who takes such liberty to call me a ****ing idiot anonymously on here wouldn't have uttered the slightest peep.
That's what I mean about perceived safety through anonymity and distance. Someday though this war of words will result in people getting really hurt. For the most part the aggression is all played out on the keyboard and eventually everyone calms down and sometimes people even get so tired of it that they manage to reprogram themselves to simply avoid it. But once in a while when one or both sides is particularly nasty it can lead to physical confrontation.
The best example of that is when Eric Hu, "Eric." here on AZB, was in a long flame fest with professional trick shot artist Larry Grindiger. Larry was relentless with the racial attacks among other things and Eric continually engaged him. (This was on the Rec.Sport.Billiard newsgroup, which was pretty much decimated by this fight)
Ultimately Eric ended up sucker punching Larry, who was about twice Eric's age, at the Super Billiards Expo in 2006. Eric was ticketed and fined and barred from the SBE for life.
A lot of us were on Eric's side and we lobbied the Hopkins to let him back in and he was allowed back in after a few years.
So this shows that hate on here can sometimes lead to violence in the real world. It's just all too easy to be hateful and spiteful through the keyboard though.
The only peaceful message board is a heavily moderated one. This one is very much undermoderated for it's size which allows for people to get away with breaking the rules on name calling and harassment too often and for too long.