What does that even mean? People are dumb. And even dumber in large mobs. And when you have powerful people deliberately misleading hordes of dummies to cause mayhem I would think that would be more of problem. Wouldn't you agree? Wouldn't you agree that at some level moderation and regulation is important.
Lets not forget that thousands of people were whipped up on Twitter (and other platforms) to try and overthrow the government based on fraudulent claims by Trump.
Free speech absolutism doesn't work. On a much deeper level there is no system in which absolute freedom is allowed that won't end in chaos.
Ask yourself why would people listen to someone advocating for violence? The issue typically isn't the person whose speech triggers violence but the underlying conditions within the country that leads people to commit said acts of violence.
For example, was it the speech of Hutu extremists that caused the Rwandan genocide in 1994 or was it the decades of pent up frustration and anger over the legacy left by the Belgiums that created deep seated hatred between the Hutus and Tutsis? If that history never occurred would extremist speech have any effect on the populous?
Stop blaming free speech for deeper seeded issues. The only reason extremist speech has any effect in galvanizing people to commit violence is because the anger already exists. All the extremist did was light the spark on a field that was gonna catch fire anyways. Solve the deeper seeded issues and you wouldn't have to worry about the speech.