I was going to watch it after seeing it advertised alongside an interview with the lad who got attacked, but after that first opening couple of minutes (when they didn't even show the attack, just a few obscure close-ups and sound clips) I decided that I didn't have he stomach for it.
I've seen and endured disturbing violence before (This Is England, Pan's Labyrinth and the grim film with Monica Bellucci and the fire extinguisher scene spring to mind), but something about this one just puts it beyond me; I think it's a combination of the sheer tragedy and heartbreak of it all, but also that these kind of stories seem to be more common nowadays (perhaps more to do with media coverage) and therefore in some way more relatable and closer to the bone, as opposed to being a real standout shock like it was 10 years ago. Also, perhaps as you get older and start to care about people in your life more, the feelings towards the victims and their families in this tragedy ascend from empathetic to sympathetic and so seeing this kind of thing cuts even deeper, particularly if you're in a relationship or have kids.