If you've spent any amount of time on online forums, you've probably seen it happen. A new poster arrives, and proceeds to make an ass of himself. (It is very rarely "herself".) If your forum is a good one, a moderator soon appears and makes it plain that the new guy needs to chill.
In most cases, it ends there. The new guy either learns to plays nice or slinks off to find another forum with looser standards of civility. But all too often, the asshole digs in his heels.
The arguments are always the same: This is a matter of principle! The right to be a jerk is the most important thing! People are too thin-skinned! Moderation is a violation of Free Speech! The mods are a bunch of fascists!
The forum locals have a good laugh at his feeble arguments, blind arrogance, and self-centered pleading. Eventually the mods get tired of his impotent raging against the machine and ban him. The last few years have seen this same experience played out on a larger scale.
When Reddit shut down r/fatpeoplehate there was a huge backlash. FPH was exactly what the name suggests, an endless five-minute-hate against fat people. The Reddit admins were content to let the community be, until complaints started. People unlucky enough to have been featured in FPH became targets of harassment campaigns. This was a potential legal problem for Reddit, so FPH had to go.
Even 4-chan, a synecdoche for Internet lawlessness, banned discussion of Gamergate for the same reason. Given the bare minimum standard of "don't be illegal" there were still those who considered it too strict.
So now the barrel has a new bottom. Gamergaters from 4-chan migrated to 8-chan, with the nazis and pedophiles. Those from FPH went to Voat, along with r/coontown and r/jailbait. But they are all unified by their mutual resentment of the "social justice warriors" that took away their supposed rights.
There has been some movement in the other direction, though. In the wake of Gamergate, there's a growing movement to prevent online abuse. Twitter has pledge to improve their harassment protection. Community sites like Imzy are banking on the idea that strong moderation makes better communities.
The social, political, and legal aspects of this phenomenon are still unfolding. Watch this space.