Modern instant gratification society & fame seeking
Everyone is a unique and special snowflake
Mommy and Daddy working until all hours to make it
Everyone is a winner
Destruction of family unit
Media hysteria and need for ratings
Feminism and castration of males
Violent video games with a reset button
Kids pumped full of meds & SSRI's
Social media in all forms
Tenants of Communism
No jobs, no futures and massive student loan debt
Removal of religion and status of a higher power
Street drugs - lots of street drugs
Sexual frustration
Violent crime and glorification of criminal elements
Unchecked immigration
Removal of forced institutionalization
Broken educational systems and zero tolerance

The list goes on and on and on...

It's not weapons. It's our modern day society we've created for ourselves. Weapons are the "easy" target to go after. The above list is really hard to tackle.
Kids and people are going to continue to die until we get it fixed. We won't get it fixed. Happy Monday....