exercise their right not to be discriminated against... Its in the constitution for crying out loud!
Yeah, the constitution really protects me as a white male in this country - I'm free from discrimination, sure...
Look, I don't want to turn this into a mudslinging match at all, but what was said was hardly racist. Making a generalisation based on a person's assumed cultural background is not always defamatory for crying in a bucket. It's akin to someone saying "Nice rifle" if it were a white man. I wouldn't see it as offensive or racist, but rather just immature and stupid.
We have created this generation of people in this country (all races) who see the solution to racism and segregation being to cry foul at every moment possible, and Malemafying every comment made. Well that's just fuelling the fire.

Now had the black guy turned around and explained to the boerboel exactly why he found it offensive, it would have opened a dialogue between the two and would have been constructive. Our leaders have done a fine job of showing us exactly how NOT to handle racism, so lets try not to take a leaf out of their book and show them how it should be done.
Personally, I think the OPs not giving the full story here at all. But hypothetically, had that comment been made and that was the be all and end all of the event, then there was a much more effective way to handle this situation. Personally, as a boss, I would have made the 2 of them sit down and discuss between each other (with a mediator of course) why the comment was deemed offensive. That is the only solution - no disciplinary action is needed unless it is a repeat offence and opening up that dialogue with a neutral third party present is more beneficial to everyone involved, the company included...