well, this isn't related in any way to "what's going on in schools" in genera, is it.
What's going on in schools in general is no funding, leading to no teachers staying in the job, leading to a poor standard of education as non specialists struggle to teach subjects they don't know, leading to poor relationships and general culture of poor behaviour, which in turn makes more teachers decide to leave.
What happened here is a violent person perpetrated a violent act, as has always and will always happen