Richard Spencer, the identitarian responsible for coining the term Alt-Right and often miscategorized as a Nazi, is not stupid. He is actually anything but. His writing and speeches lay out an intellectual, yet superficial and flawed case for his worldview that has pulled the wool over the eyes of many able-bodied young males, as evidenced by Charlottesville. He does not condone violence, but rather, wants to achieve his objectives through open discourse. Punching him in the face only makes him look more reasonable. It only lends support to the idea that he cannot be challenged intellectually, thus building his following. As much as people want to conflate their Antifa water balloon street brawl with the allies storming Normandy, it just isn't accurate.
If we are to agree to the assumption that all ideas are paramount to the progress of intellectual consciousness, personal and collective, then we must submit that the protection of all ideas outweighs the damage some of those ideas may wreak in their full fruition.