A valid refutation, if a little weak.
I think the last paragraph of the "What Popper actually Said" section is just as important to note:
> It makes sense, doesn't it? Free speech is all fine and dandy, but let's stretch that to the limit. A and B are promoting their ideologies. A-ism is based on reasoned arguments — they may not yield correct conclusions, or they may, but A is speaking in good faith. B-ism is based on calls to violence and insurrection. If both are afforded the right to speak freely, modelling things out, B will necessarily inflict violence, or threats of such, on A — but violence and violent threats have the effect of silencing others, which indirectly impedes their right to speak freely — you are not 'free' to speak if someone will hurt you for doing so! Thus, free will is replaced with coercion, and society suffers as a result.
A line in speech has to be drawn somewhere. There's a difference among "I hate $RACE", "I hate $RACIAL_SLUR", "Someone needs to deal with the $RACIAL_SLUR problem", and "I want to kill $RACIAL_SLUR".
The first two on their own are not violent, and they're not written to stoke violence, but a person that sees as a lot of that content who agrees with it may eventually decide to escalate to violence.
The latter two are easily considered calls to violence, which even most free speech advocates might not agree with. The most aggravating thing about the people that post that kind of content is the blindingly obvious bad faith claims that "Oh, I don't mean we should solve the problem by KILLING them!" or "Well, I'd never ACTUALLY kill someone".
It's extremely easy to say "Well until the murder happens, no crime has been committed" when you're not the target.