Hatred and murder has always existed! The idea that online discussion forums create or foment hatred is laughable. That hatred has always been out there. Now people just have a place to vent. The good part about it being out in the open is that we can actually see it and be aware of it.
In this case, the idea is to lose a bit of free speech, and gain less hatred and less murder. That is not an arbitrary judgement; admittedly this is also not a clear-cut judgement.
The system never works itself out, successful societies are the ones which have established governing rules. Game theory has given us pretty good indication that systems rather self-destruct without governance than self-stabilize.