I blame all violent movies and games. I mean, violence is around us all the time, whether it's fictional or not, and all people obviously can't understand the difference. As you say, fireworks can be as dangerous as grenades - it can hurt or even kill you or the people around you.
Fireworks is good only when it's used in the right way: out of harm's way.
ReFreezed
Some people doesn't seem to understand that they're dealing with explosives. It's just toys to them.
MrShankly
Exactly, you wonder sometimes if people realise that what they're throwing around could be as dangerous as high end exlosives like grenades, they still do massive amounts of harm, that and people don't seem to look at death with the same seriousness anymore, i can't imaginee why this is.