...or it's the difference between using it in slang vs using it as an insult/perjorative. And people usually get that. The whole hard R thing represents that difference really well. There's nothing wrong with taking back power over a slur. I can't think of any better way to mock the people who use it, in fact.

Generally speaking, the group taking back the slur isn't going to use it in a bad way, so it's assumed they're using friendly slang. If you aren't part of that group, that basic assumption isn't there. And considering how many racists are still alive today, that's fair. For me, it's also just basic respect. The slur isn't used against me and probably won't be. I have nothing to reclaim.

~~Look at it this way. Eminem has gone his entire rap career without saying it. He's really good friends and colleagues with a lot of black people. Undoubtedly someone has "given him permission" at some point, and I imagine almost everyone he's with would be fine with it, but he still doesn't use it.~~

It's ironic, actually. The people who understand this are also probably the people most likely to be "given permission". And they don't use it. That should tell you everything you need to know.

Edit: Correction, he had used it in the past, but he stopped quite a while ago. The general gist my point though is still the same, he's built an incredible rap career without saying it much at all, and he clearly hasn't seen the need to in a long time.