I really hate the use of this phrase, it lacks specificity and has a sort of unknown unknowns quality whereby we are meant to believe that some speaker utters vilification until some threshold is met and some unknowable person will be impelled to violence. It feels like one of those concepts that oozes out of intelligence connected think tanks and into the discourse. It completely lacks any predictive power and is entirely about crafting narratives around lone actors committing political violence.