Thanks for your article- you make a very valid point. No person should be treated like that and we should all be brave enough to stand up and say something when we see it happening.
However, I don’t think that it’s entirely constructive to appeal to white people only in your article. What you witnessed is the kind of behaviour that results when a person of higher socio-economic standing starts to look down upon those less fortunate than them. In South Africa this often equates to a white person looking down on a person of colour; however there are many occasions on which black people treat others just as badly. We should not tolerate or condone this behaviour, regardless of it’s perpetrator, but neither should we assume that it is inherent to or only found in one group of people.