I fail to see how victimizing someone else is YOUR freedom of expression. There is a very distinct difference between calling someone a name in passing and calling someone a name every single day, pushing them in the halls, spreading nasty rumors, and overall destroying that person in any way possible. You may think you deserve that right, but you're wrong. People deserve to be protected from such abuse, and it IS abuse.
And bullying is not just a normal part of growing up - it's gotten much worse over the years because people are not held accountable. Back in the day if you picked on someone and got your ass handed to you, everyone said you got what you deserved and didn't punish the other kid. Now victims either take the abuse or they try to stand up for themselves and get victimized by the system. It's wrong, and I think anyone who defends it as "kids being kids" is/was either a.) a bully themselves, b.) never suffered from being bullied, or c.) is just too immature to realize there's no place for it.