Cal it a freak accident, whatever else you want.
Forget the "sports" orientation and any patriotism about national pastimes for a moment.
Forget too the fond memories of what we did as kids and got away with only a few scrapes.
It is still PREDICTABLE that young teens throwing hard objects with all their might in the general direction of each other will (statistically) lead to some number of serious injuries and deaths.
I am not a big fan of "Helmets for anything/everything", but Murphy being ever present, whatever CAN happen eventually WILL happen.
Safety vests to protect the rib cage ARE showing up in more and more "Sports".
BTW, I don't know if it is still true, but supposedly at one time more people got killed playing cricket than in the boxing ring.