Gun control is a "third rail" in many political jurisdictions in the USA. Many Americans will vote against any agent who would disarm them; those voters are unlikely to see disarming to diminish the (very roughly) ~0.000001% chance of death by mass shooting as a sensible--or even Constitutional--trade.

thats all they're doing

>public is not made aware of this very tragic problem

everyone is quite aware of what the problems are, many view the children murdered during Sandy Hook as the end of the conversation. The decisions were made.

most first world countries have solved these problems, the US meanwhile...

‘No Way To Prevent This,’ Says Only Nation Where This Regularly Happens