The problem with what you're saying is that incivility does not directly cause death. I could not actually kill you by writing a lot of really clever insults, not even if they were worthy of Guybrush Threepwood. The deaths "caused" by insults are in fact mediated through rare mental illnesses, and that calls in to question the issue of responsibility. If you bumped into me on the sidewalk and, because a rare illness made me extremely sensitive to impacts, I died, a court would not hold you responsibly like they would me if I hit you with a car. The degree to which the effect of the cause is typical matters a lot in designing legislation or making fair decisions that apply equally to everyone.