Earlier quoted context omitted.
I actually think apartheid is a good example of why the moral thing to do sometimes is to harm others and/or destroy property. It's not hard to argue at all. Preventing the suffering of the many by harming a relatively small number of people (or destroying practically any amount of property, really) is a clear win from a utilitarian perspective.
I understand your perspective and realize it's an easy argument to make. I see the same arguments about America's use of the atomic bomb in WW2. There is not much more to say on this topic with two opposing viewpoints :)
Only that use was totally unjustified, as Japan was surrendering anyway, a military defeat was already 100% feasible, and the bomb was used needlessy to send a message to the USSR.