You knew the answer before you asked the question Rooster. 
It's human nature, when there's no accountability especially for some people, when there are no fences to make good neighbors......that and the more salient fact that, anonymity from a computer room hundreds and thousands of miles away from center mass, and a lack of face to face accountability. It emboldens everyone with their own small sense of security. Now....if the computer cops could kick in our doors and shine a bright flashlight on us all for the things we say, I'd like to suggest that the answers we give would be more reasoned. Of course, having prepped for just that eventuality, I took it upon myself to hide the batteries for the flashlights 
.....but you get what I mean.
You'll never remove the stimuli.....in this case anonymity, unless the one condition to joining a website was to have a camera attached to the top of your screen, but even then.....
I also have a theory of course, one which I believe I'm spot on with, and that is the belief that for every one of those who belong to either one or a number of sites, they are dwarfed by those who lurk. I think lurking is THE number one past time of people who know all the opinion based web sites.....once you're infected, you're either a voyeur or that moth attracted to light.
And of course, no one ever attached behavior to it's wings.