A better comparison would be calling a woman a cunt, as a whore is a synonym for prostitute which can accurately describe an individual's profession, ergo a sentiment which can both be an insult and a descriptor.

With that said, imagine a scenario where a woman runs over your daughter, keeps driving while flipping the bird, you call an ambulance and describe the situation as "my daughter almost died due to some CUNT!"  Now, women of all kinds attack you for using that word, paying no mind to the fact that a woman just ran over an innocent girl without a second thought.  You might describe the individuals who ignore the actions of the woman driver, ignore the daughter, and instead attack you for using a word they didn't like as, themselves, soulless cunts.

We can see, then, why some people take offense to "nigger", and why some do not: it's the same reason why cunts don't like being called cunts and, to a much greater extent, why evil cannot bare to hear the truth.  Are all women cunts?  Of course not, it's a gross over-generalization to presume half the world is this way, and to call a nice woman a cunt is very bad form, to which they deserve the defense, to which people would ask that the individual who muttered the obscenity swallow their words and offer an apology--this, I find fair.  But when a woman is a cunt, only those who are personally offended by being called a cunt--a revelation of truth--will come to her defense: only evil has an incentive to mask evil.

So, with this sorted out, we can clearly see whether Bruno is being asked to apologize for calling a decent man what he isn't, or if evil is defending evil.