Many forums and scientists. Much of the science was initiated by a famous study - The Stanford Prison Experiment in which some individuals were randomly assigned to play the role of guards and other students were assigned the role of playing prisoners. The experiment had to be stopped because the guards began humiliating and beating the prisoners. The conditions where this effect is most likely to occur is when the powerful have little fear of being held accountable for their actions and when there is a sense of anonymity between guards and the prisoners. In other words, just like most Internet forums. Googling "Standford Prison Experiment" "forum moderation" gets you over 40,000 hits.
The good news is there is a solution to this problem. It's been proven to work time and time again.
However, the bad news is that people don't usually go along with what psychologists recommend and although people like to make lots of excuses and personal attacks to avoid making the change, the real reason, again according to psychologists, is that they don't like to give up their power. That's the problem with billionaires, forum moderators and anyone else who gets a taste of power.
So if you're not convinced by psychologists, why not try Rev. Martin Luther King, Jr., Ph.D. His drum major instinct speech pulls all the various disciplines and ideas together by that special magic he had. As usual he says it better than anyone else.