The dog in question was called what it was - we cannot change that. However, we don't need to perpetuate the use of words that cause pain, suffering and offence. The words that my grandparents used are not the words that I would use, and language will evolve again ad infinitum. I think that it is right (and overdue) that we have a full and frank conversation about how we as a nation have historically treated other people - and that goes for all nations and about all people, the UK are not the only nation guilty of violating others.
As Greensleeves alluded to - history doesn't stop, we make it everyday! We have to embrace change and move forward to ensure true equality happens for all humans.