"Material harm"? As in physical harm via threats of violence or calls to violent behavior? Or emotional and damaging harm? I honestly think people should generally just be nicer, it's more productive.
Kayne saying "death", but he has since claimed he reversed "def" and "death", that tweet is understandably considered violence. I don't believe hate is violence. I believe this is a common misconception of people who haven't experienced actual violence or true personal danger. I in no way claim this should be some right of passage. Speach isn't deformative or physically damaging. The idea speach is a "frontier" or is the "catalyst" is misleading. Many organizations have direct calls to action for violence and are still posting today.