"Why do people seek revenge online?"
That's an easy one. For nameless, faceless, wimps, it is easier to sit behind a keyboard & punch away with no fear of retribution. IP addresses can only be traced by the ADMIN of a message board (ie iHub) or unless a moron sends an email to someone he gets into a beef with on a thread & leaves a fingerprint. IMHO, individual posters can post with anonymity with other posters so bravado shines. It is only the ADMIN that, should they really want to, can find out the people behind the aliases.
"Why do 'bashers' exist? Why do touts exist?"
Also easy...Cause $$$$ are involved. Everyone is out for themselves & the some people actually believe that by bashing or touting a particular stock, the price will move thereby causing them to profit.
I don't see these as very complicated issues...only MHO.