There’s a myriad of reasons for the spike in gun violence, namely its connection to the mental health crisis, but since the government has shown that it really doesn’t care about people these things continue to happen.
A lot of mass murderers tell someone [via a manifesto] before they commit a crime, and it’s a well known fact that this is the case, so if it was a priority to anyone there’d be better policies regarding how to respond to threatening messages posted online.