I've got to be honest, cyberbullying (and other social harassment) is a FUCKTON harder to avoid on the internet than in real life. Especially on places like facebook where there is no anonymity because its an extension of your real life social network (usually). Your options are basically use facebook or don't use facebook. And even if you choose NOT to use facebook, your friends will, and if the guy is going around messaging all your friends about how much of a whore your dead daughter was, you're probably going to have trouble getting away from it.
If you meet someone in real-life who's an asshole, you just stay the hell away from them. If they hit you, big whoop, you get a little bruised, I don't think getting hit is usually enough to make someone kill themselves (and then you can charge them with assault, problem solved). And if they start following you around, showing up at your house, dropping messages off in your mailbox, interrupting dinners and movies out with friends... well, they get brought in for harassment. Especially if they are doing it solely to hurt you.
On the internet, we aren't so lucky. A sufficiently dedicated troll WILL find, will ruin your good name (even if its psudeonymous), and can make your online social life a living hell, and just the feeling of knowing someone is always going to be there waiting to hurt you, I can see how that would be incredibly damaging.
If you don't understand how a cyber-bully can push someone to suicide, I don't see how you believe its possible for anyone to ever be pushed to suicide by anyone. I'm making no comment on the legality thereof, but I don't see how it would work much different than it does in real life.