I'm not quite sure how these are inherently in conflict. It seems like a community might allow the use of slurs as insults while also discouraging insults in general. In different words, "Please be nice to each other. We don't ban for the use of any particular words, but we do ban for disparaging others."

I could easily imagine a policy like this in, say, a linguistics forum, where it's totally allowed to discuss the usage of slurs, as long as they're not directed at someone.