That first sentence is an absolute moral position without any real justification, and the second is factually questionable.
Shutting down certain communications channels, or removing specific messages from them, can absolutely change behavior. Just like social media can drive a revolution, it can drive any collective action, including negative ones.
True, so do we start regulating 4chan, tor and other means of certain communications that can leas to negative effects? Twich cos you could get swatted? I mean, all channels will usually have positives and negatives and it always comes down to who will be the arbiter of what is positive or negative. I am afraid of those people cos i used to live in communism and they are the weak link in resisting censorship...
Shutting down communication channels will not stop violence.