That is obviously also a possibility; I'm not arguing that they should be silenced by default, only that it is possible and should not be beyond the reach of a society's purview to do so. For the moment, it seems more plausible that violence erupts due to persuasion and incitement, which is why (for instance) there are already laws against incitement but not against illegalising speech lest it cause high tensions. I assume this question can also be answered empirically.
In the tension between freedom of speech and preventing harmful speech, I wonder if we're approach a Nash equilibrium, or if it's more of an accelerating oscillator.
