I know little or nothing about Eminem (or Slim Shady).

But I know that ideas, any ideas, should be out in the air. Stuff kept in the dark festers and inevitably comes out worse than it originally was. Let out, they can be looked at, talked about and changed.

You need to think about what constitutes 'harm'. Being offended or upset by something isn't harmful. When damaged people cause harm, it's because they're damaged, and whatever they've read, heard or seen that affects what they do is not, in and of itself, to blame.