Seventeen people were killed and fourteen more were taken to hospitals, making it one of the world's deadliest school massacres. The suspected perpetrator, 19-year-old Nikolas Cruz, was identified by witnesses and arrested shortly afterward.
Invading other countries and maintaining a war there is also crucial, in order for one of your biggest industries to make more profits and thus helping your economy to grow. War is a profitable business, for such economic models.
Just watch any of the Hollywood action films and you will see how many models of guns and other weaponry are being "advertised" subconsciously to the audience. Carrying a gun, is considered so natural in some communities in the US that as a solution to the increasing number of innocent victims shot at schools, is seen to arm the teachers.
America, of course, is not the only country to be blamed. Its European counterparts and NATO allies, have also a fair share of the blame. Countries such as France and the UK are making profits from arms sales in countries that suffer from on-going conflicts.