When I have ever said that someone can do whatever they what? A persons rights end when they effect the rights of others. (directly, and negatively) that's why you can't steal from people. Or murder them.
You do not have a right not be be offended. (this is especially true when you concideir that it's not someone else that offends you, but your opinion that another's action should be offensive)
On of the reasons the first amendment was put forth to protect offensive speech.