"True massacres" of which Mother Jones -- a source I put much more credit in than Reddit -- says there were four this year. The bottom line with these is simple, "Against such an attack, it's better to have a shootout than a one sided massacre." The case for hoping there's a least one defender to shoot back instantly and thus minimize carnage is compelling. That a three- to five-minute response is too late is also pretty clear. It argues strongly in favor of the "fight" option. The argument of defense through pacifism further softening society as a target does not compute in this type of scenario unless a very harsh decision is made.
The "fight" option has a cost. As such a category of threat rises, creating the social and skills conditions to safely have such a level of aggregate defense becomes a challenge. It's a challenge not just for those willing to participate in being the defenders; it's also a challenge for those who are undefended to see their survival now depending on not just those with badges but those without them in their midst as well. It's an artifact of a more dangerous world condition; one we in the United States had hoped was in our past by has apparently shown to us to have only been a very lucky and temporary reprieve.
What we must decide as a society is whether the overall danger level has shifted to a level where a more prepared to fight approach has become the more prudent one to respond to the moment. It does not mean such a posture is forever; but it does imply we've recognized that it is until we've determined that the causes behind the wave of violence have dissipated.
Or, and this is a harsh but central question, is the loss count too low vs. the level of social change being asked so that society decides it's better to take the deaths rather than change our ways.
We are all asking this question with deep trepidation because it's an important question affecting all of us. We'd all rather live long and peaceful lives and pass that legacy to our children. It's not as free a ride as we'd hoped. So here we sit on the raggedy edge.