Azizi - I've just looked at the DT version and seen the 'N' word. Never have seen/heard it before in any version I have heard sung. Being English, I first heard Lonnies version as a youngster. 50+ yrs later, it is still sung here as a singalong song. No-one I have met ever associated it with slavery of any sort - just hard, low paid work and bragging 'I am the best'. I find that persons with a 'hard' viewpoint on any topic will turn any subject to their view. Most singers will of heard Leadbellys version (by a black man - recorded well after slavery was abolished)and based their rendition on this. No-one is condoning slavery/racism of any sort but if all songs with an unsavoury connection were abolished the traditional British songs of 'taking the Kings shilling' and being shanghaied etc. would die out.
I won't sing any Irish protest songs due to the IRA atrocities but that is my decision. I also admit that they are good, rousing songs though.