It is a serious concern.
Good! (that they are charged); several more should see the same.
There were swarming attacks in greater numbers 30 years ago. Every generation laments 'Kids these days' or 'Where are the parents'.
While in some cases, no doubt, bad/negligent parenting may be a factor; it has been ever so.
I don't think there is any indication its worse now than a generation prior. After all, the homicide rate and shootings are not only at 5-year lows, but much lower today than they were when most UT'ers were young adults!
Which is not to in anyway minimize the current spate of incidents, particularly on the TTC; which seems to be some mixture of mental illness, along with some mal-adjusted teens and their would-be copycats.
We need most of all need to address the mental illness side of things with far more treatment available at no-cost, virtually on-demand (no deferring needed intervention); with greater outreach to those that may need help.
For the mal adjusted teens, enforcement with some meaningful consequences is in order; and if there is any evidence of one particular social media platform or one or two particular high schools where things are uniquely out of hand, then appropriate intervention is required.