I think the freedom of speech should protect the abillity of people to do things like keep "Death Lists" if they really feel like it. Acting on such an impulse is one thing, but this is something else entirely. What's more violence and a desire for revenge, even murder, are part of human nature, a point which is made in song, books, movies, and artwork through the ages. Trying to ignore the problem or punish the kid doesn't change the fundemental way we are wired.
What's more, "Death Note" has become fairly mainstream due to the contreversy, it's pure fantasy, and people should realize it. It doesn't even have the same backround behind it as Voodoo or whatever, and they sell Voodoo kits and such to make dolls of people you don't like in bloody Borders books (or they did, in those little tiny gift box things near the register), not to mention all the other places you can get them.
Simply put it's a way of blowing off steam, and I feel the same way about it as I do suspending kids for drawing violent pictures, or having guns depicted somewhere on their clothing, or whatever else. Truthfully, I was concerned about things going to these levels back when *I* was a kid (even if I didn't have a normal childhood) and rulings were being made saying that kids didn't have the same rights as adults under the constitution and such, allowing for school regulation. Fears that things would go this far were dismissed as "silly" and "alarmist" but here we are, although admittedly it did take Columbine and a few other incidents to get the ball rolling to this point.
At any rate, that's my opinion. I understand the logic, but when you get down to it, all the kid is doing is making a list of names in a notebook. That's his right. Heck, I have the right to write all kinds of horrible plans of vengeance in a personal diary if I want to as well. It might come up as evidence if something happens to those people similar to what I write and someone knows it, but it's both my right and the risk I take.
What's more I will say that I've heard a lot of horror writers/creators were inspired by their own thoughts of vengeance and stuff in school. Some even going so far as to make a point about the reality of locales where certain things happen. This kid's imagintive revenge fantasies might very well make him the next Steven King, Clive Barker, Dean Koontz, etc...