Good list.
Conservatives and many older Americans I would place in the "not listening" list. Many of those not listening believe the US is going to hell in a handbasket, that things like this will happen again, and that nothing can be done. Younger Americans-- many of whom attend college or university-- are not buying it or accepting it.
Minorities will come around and support changes, especially if these changes include putting metal detectors and extra security around wealthy, suburban, predominantly white schools, not just the schools their own children attend. Others will hate such security measures, but will adjust, just as we have done with airport security.
Maybe. Older liberals maybe. Far-right older conservatives, maybe not.
Wealthy white millennial conservatives, maybe not.