It is never a good thing when people in a society start killing each other with a greater degree of frequency. But incidents of this type are the natural consequence of 50 years of economic and social policies that have turned the USA into a Third World society with First World technology. We now have the class relations and governmental incompetence of Latin America and the number of Americans who have had unpleasant encounters with members of state security forces is now approaching that found in traditional oligarchies and dictatorships as well.
The world-historical norm is stratified societies in which periodic mass rebellions and ongoing localized rebellions take place. Terrorist/guerrilla/lone wolf violence against members of state security forces are common in many societies. During the Roman occupation of the Judaic region, Zealots would engage in knife attacks on Roman soldiers. Medieval peasants would attack the king’s knights. Many Latin American, African, Middle Eastern, Pacific, and Asian countries experience this all the time, including regions within major powers like Russia, China, and India. Americans are used to living in a predominantly middle-class affluent society where political violence rare. Now that’s starting to change.